1. a particular mood that influences your behaviour
be in the right/wrong frame of mind to do something
Your 'frame of mind' is the mood you are in or the attitude you have. If you are in the 'right frame of mind' you are in a good place mentally to do something or achieve something. If you are in the 'wrong frame of mind' you do not have the right attitude in order to approach or complete a task. You will hear these phrases used often in social and professional contexts.