In questions about the dimensions of health, they'll either ask for DEFINITIONS of EXAMPLES.
When they ask for examples for a dimension, the things you listed are brilliant. My go-to ones are fitness (and capacity to perform physical tasks as a backup) for physical, levels of self-esteem for mental and being able to interact with others (and maintain relationships as a backup) for social.
When they ask for definitions, pretty much go with the ones in the study design. They don't have to be word for word, but the thing is, if its in the study design, you know it's not wrong, so anything that conveys the same points should get you the marks.
Usually they ask for the definition PLUS an example, so then you just say the definition and then mention an example (or two if you're like me and always put too much information down because you're pedantic).