adjective · to be on good terms with or to suit each other

他们两人挺谈得对头。

adjective · correct, normal, or on the right track

这道题的计算思路好像不太对头。

adjective · being hostile, antagonistic, or in a state of opposition

他们两家因为地界问题一直不对头，经常发生争执。

noun · a person or group that is a longstanding enemy, adversary, or rival

他们两家是几十年的老对头了。