Bone of contention(idiom)
An unresolved problem, dispute, or disagreement.
Hindi meaning:असहमति का मुख्य मुद्दा
Synonyms: Controversy, Altercation, Disagreement, Problem, Debate
Example: Jerry leaving his dirty dishes in the sink for days became a bone of contention between him and his roommate.
Trick to remember: Bone ban gyi Bone of contention 
