Having a crush, they may give a sob (4)
I believe the answer is:
boas
'having a crush they' is the definition.
The definition suggests an adverb but the answer is not.
'may give a sob' is the wordplay.
'may' is an anagram indicator (I've seen 'might' mean this (I've seen this in other clues)).
'give' says to put letters next to each other.
'a' next to 'sob' is 'asob'.
'asob' with letters rearranged gives 'BOAS'.
Can you help me to learn more?
(Other definitions for boas that I've seen before include "Long fluffy scarves of feathers" , "21 [SNAKES]" , "Cold-blooded creatures" , "Large snakes" .)