Crack up under current allegation (7)
I believe the answer is:
acclaim
'crack up' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe there's a link between them I don't understand?
'under current allegation' is the wordplay.
'under' says to put letters next to each other.
'current' becomes 'ac' (alternating current).
'allegation' becomes 'claim' (I've seen this in another clue).
'ac' next to 'claim' is 'ACCLAIM'.
Can you help me to learn more?
(Other definitions for acclaim that I've seen before include "Salute, applaud" , "Cheer" , "Welcome with shouts of approval" , "Great public praise" , "Welcome enthusiastically" .)