Show courtesy to a lady but not to a girlfriend (5,2)
I believe the answer is:
stand up
'show' is the definition.
The definition and answer can be both to do with communicating as well as being verbs in their base form.
Perhaps there's a link between them I don't understand?
'courtesy to a lady but not to a girlfriend' is the wordplay.
I cannot really understand how this works, but
'a' could be 'an' and 'an' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for stand up that I've seen before include "Kind of comedian" , "To wash" , "Fail to keep appointment" , "Miss date" , "Survive examination" .)