Maybe Holly's husband stuck behind large vehicle (4)
I believe the answer is:
bush
'maybe holly's' is the definition.
I can't tell whether this definition defines the answer.
'husband stuck behind large vehicle' is the wordplay.
'husband' becomes 'h' (abbreviation).
'stuck behind' is a charade indicator (letters next to each other) (I've seen this in other clues).
'large vehicle' becomes 'bus' (I've seen this before).
'h' put after 'bus' is 'BUSH'.
Can you help me to learn more?
(Other definitions for bush that I've seen before include "A shrub or a modern president" , "US president(s) - source of gooseberries" , "Low, woody plant" , "George or George W." , "ex-president" .)