Insect seen in meadow, a spittlebug (4)
I believe the answer is:
wasp
'insect' is the definition.
(wasp is a kind of insect)
'in meadow a spittlebug' is the wordplay.
'in' indicates a hidden word.
'WASP' is hidden in the letters of 'meadow a spittlebug'.
'seen' acts as a link.
(Other definitions for wasp that I've seen before include "Insect with a sting in its tail" , "Social worker" , "Swap for a stinging insect" , "Stingy type" , "Insect; thin (waist)" .)