Relevant is an adjective as is relative. Relevant means something that applies to your topic. For example- in my English class i was taught RELEVANT things like grammar. I am learning about verbs because it is relevant to my English course. Relative has more meanings- It means family members. My mother is a relative of mine. So are my uncles, cousins, aunts, etc. It can also mean 'in relation to' or 'compared to'. For example: the dog is small, relative to an elephant.