Get together with a redhead friend (5)
I believe the answer is:
rally
'get together' is the definition.
(rallying is a kind of getting together)
'with a redhead friend' is the wordplay.
'with' says to put letters next to each other.
'a redhead' becomes 'r' (the head/first letter of 'red').
'friend' becomes 'ally' (I've seen this before).
'r' next to 'ally' is 'RALLY'.
(Other definitions for rally that I've seen before include "recovery" , "Mass political meeting" , "Recover strength after illness" , "Arouse for action" , "motoring event" .)