Exactly meaning is "If you don't like to do, don't do it"
하기 : 하다 (to do) + 기 = doing (Noun)
싫으면 : 싫다 (hate, don't like) + 으면 (if) = if hate (if don't like)
- Vstem(으)면 : "if" form.
+ 으면 when Verbs have ending consonant.(받침 있음)
+ 면 when Verbs have not ending consonant (받침 없음)
- 하지 마: This is the informal form of 하지 마세요;
(Please don't ...)
+ V지 마세요 (Note that is Verb stem, you don't need to conjugation it)
More example:
가지 마세요! - Please don't go!
말하지 마세요- Please don't say!