I'm just going to go contrary (because why not) to everyone on this thread and encourage you to expand it - but on the condition that you think it's fun and enjoyable. Like I mean it - go nuts.
I know for sure that I have trouble recalling words, and it's always sort of pesky when you have to lean on words/phrases that are either a) inadequate or b) too hefty for something which you want to subtly hint on. So I think making lists is pretty helpful. Expansive vocabulary is absolutely paramount to good (or what I consider to be good, anyway) writing because it gives you so much advantage in how you would like to shape/pitch an idea. It may not be the best idea to improve a VCE english essay - but it is good for writing in general. I don't think you can argue against that (you can, but yknow I'm trying to make a case here). Whether it is to draw on a particular aspect of an object/characteristic or whatever or to compound feelings into a satisfying compact sexiness - vocabulary gives potential for all sorts of life and colours, I believe.
So, from the start of this year I started compiling words I never found from just simply scrolling through synonym lists. I'll put it down below, and I'll continue to update it when I find new ones. I think it's an absolute luxury to be exposed to different words, but yes, while I don't recommend it purely for year 12 study - I recommend it because it is good for life. I mean words are just so beautiful sometimes, I just want to hug them and have them consume me.
Anyway, the best way I found to incorporate any ol' vocabulary into your life is to experiment with it - and use it at any opportunity you get with it. Prepare to sound stupid, but do it anyway. It's also helpful to have extremely pretentious/snobbish friends, but yah know - we don't all have that 'luxury'. In any case, I'd recommend watching how authors/brilliant thinkers speak the way they do as well. The most verbal people tend to be better writers - so I'd recommend just searching their name on youtube and watch and mimic etc. I'm not kinda actively encouraging unoriginality or whatever - but it's really a different and perhaps underrated way to sort of learn/approach writing, which while I'm here - I believe is an extension of speaking. Check out Susan Sontag for example and how she articulates her thoughts. Like, she's an example of a really good thinker, you could sort of glean from.
Personal vocab list in no particular order
Cordoned (out/ something off)
Consternation (a feeling of anxiety or dismay)
apotheosis (highest point in development)
putative (generally considered or reputed to be)
chimerical (fantastical; illusory)
recondite (little known; abstruse)
litany (religious repetitious recitations ie. amen, or glory to the bead etc.)
quandary (a state of uncertainty over what to do in a difficult situation)
lode ( a vein of metal ore in the earth)
parochial (church-ish/ narrow in scope)
behest (a person’s command)
peregrination (a journey; meandering yarn)
platitude (thoughtful remark)
everted (turned inside out)
redoubt (temporary fortification)
preclude (make impossible)
apostasy (the renunciation of a religious/political belief)
peroration (concluding part of a speech; i.e.. inspirational part)
unabashed (not embarrassed)
malaise (a discomfort; a feeling difficult to pinpoint)
unbidden (without having been commanded/invited)
vicarious (experienced in the imagination)
acme (the point at which something is at its best)
calve (give birth to a calf/ to split; genesis)
iconoclast (destroyer of religious images)
impinges (to have an effect/usually negative)
oubliette (a dungeon)
accretion (growth by gradual accumulation of matter/layers)
cunctatory (from latin cunctor ‘to delay’)
coralline (derived from corals)
seance (a meeting to contact the dead)
coterie (a small group with shared interest)
priapic (relating to the phallus)
captious (tendency to find petty faults)
opprobrium (public disgrace arising from shameful conduct)
insurrection (violent uprising against authority)
hebdomadal (weekly)
antipathetic (showing/feeling a strong aversion)
chagrin (distress which follows humiliation)
anathema (something or someone that one vehemently dislikes)
parity (state of being equal)
sartorial (relating to clothes)
bedevil (cause trouble to; to beset from the path of righteousness)
ephemeral (lasting for a short time)
hermeneutic (interpretation concerning particularly the bible)
diaspora (dispersion of jews from Israel)
temerity (audacious; excessively confident)
inveigh (to speak/write about something with great hostility)
megalomania (obsession with an excess of power; ie. Kurtz)
genuflect (to bow in worship)
excogitate (to think out/ devise)
corollary (a natural consequence/proposition of something proven true)
foisted (to impose something on someone/thing)
grist (useful material for an argument etc)
moratorium (temporary prohibition)
perdurable (imperishable)
invective (insulting; highly critical language)
axiomatic (unquestionable)
covet (yearn to possess)
callowness (immature)
abstemious (indulging only in moderation)
parsimonious (unwilling to spend money)
jeremiad (long mournful complaint)
antecedent (preceding what follows logically)
lacuna (a missing portion of a book/ unfilled gap)
enervate (make someone feel drained)
paucity (something in small or insufficient quantity)
dour (gloomy; relentlessly severe)
brio (vigour or vivacity of style or performance)
meretricious (apparently attractive but having no real value)
zephyr (a gentle breeze)
coruscating (flashing/sparkling)
dross (something regarded as useless/rubbish)
mendacity (untruthfulness)
deracinated (to uproot someone from their natural place)
benighted (overtaken by darkness/ a state of contemptible intellectual ignorance)
crepuscular (relating to twilight)
succour (support in times of hardship)
buttress (reinforce)
hagiography (a biography that treats its subject with undue reverence)
impervious (not allowing fluid to pass through)
risible (provoking laughter through being ludicrous)
concomitant (naturally accompanying or associated)
ancillary (something which functions supplementarily)
intractable (hard to control or deal with)
demiurge (a being responsible for the creation of the universe)
anodyne (not likely to cause offence; dull)
iridescent (luminous colours that show differently at different angles)
disquisition (a long/elaborate essay or discussion on a particular topic)
purview (the scope of influence or concerns of something)
imbibing (drink (alcohol)/absorb)
rebarbative (unattractive/objectionable)
coterminous (sharing boundaries with)
Also other words (but more common):
resembles
fracturing
defamiliarisation
estrangement
vanishing
unflinchingly
hallucinatory
belongs
vaudeville
matrix
progeny
winnow (sifting grains)
eudaemonia
odalisque
EDIT:
Updated vocabulary
peripatetic ( n. Aristotelian/a person who travels from place to place briefly for work etc/ adj. travelling from place to place)
vertiginous (extremely steep/high)
liminal (initial stage of a process/occupying a position at a threshold or boundary)
replete (sated/very full)
orotund (resonant/pretentious/imposing; describing —> voice)
lapidary (of language - elegant and precise)
nadir (lowest point/most unsuccessful point in a situation)