Tweet about redhead with cool clothing (5)
I believe the answer is:
chirp
'tweet' is the definition.
(thesaurus)
'about redhead with cool clothing' is the wordplay.
'about' becomes 'c' (abbreviation for 'circa').
'redhead' becomes 'r' (the head/first letter of 'red').
'with cool' becomes 'hip' (I am not sure about the 'with' bit.**).
'clothing' is an insertion indicator.
'r' placed within 'hip' is 'hirp'.
'c'+'hirp'='CHIRP'
(Other definitions for chirp that I've seen before include "Sound made by small bird" , "Fledgling's sound" , "Short sharp tone of grasshopper" , "Tweet" , "Grasshopper's noise" .)