Theatre oddly repeated about a private conversation (4-1-4)
I believe the answer is:
tete-a-tete
'private conversation' is the definition.
(I've seen this before)
'theatre oddly repeated about a' is the wordplay.
'oddly' indicates alternate letters (letters in odd-numbered positions).
'repeated' shows that letters should be duplicated.
'about' is an insertion indicator.
The alternate letters of 'theatre' are 'tete'.
'tete' doubled is 'tetetete'.
'tetetete' enclosing 'a' is 'TETE-A-TETE'.
(Other definitions for tete-a-tete that I've seen before include "Private conversation between two people as in France" , "Private conversation between two French people" , "Private meeting" , "One-to-one meeting" , "Private couple's conversation" .)