Lapwing regularly dropped bristly growth on grass (3)
I believe the answer is:
awn
'dropped bristly growth on grass' is the definition.
I can't tell whether this defines the answer.
'lapwing regularly' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternate letters of 'lapwing' are 'AWN'.
Can you help me to learn more?
(Other definitions for awn that I've seen before include "Bristle-like appendage on grass" , "bit of cereal" , "Bristly growth" , "Beard of plant" , "Bristly head of barley sheath, quite wan" .)