Garden visitor from Coombe enters (3)
I believe the answer is:
bee
'garden visitor' is the definition.
(I've seen this in another clue)
'from coombe enters' is the wordplay.
'from' indicates a hidden word.
'BEE' can be found hidden inside 'coombe enters'.
(Other definitions for bee that I've seen before include "Honey producer" , "In one's bonnet, it's a persistent idea" , "Honey-making insect" , "Social gathering" , "Busy buzzer" .)