Laugh when her colt bolts (7)
I believe the answer is:
chortle
'laugh' is the definition.
(chortle is a kind of laugh)
'her colt bolts' is the wordplay.
'her colt' can be anagrammed to 'CHORTLE'.
But, I'm not sure how the anagram is indicated.
'when' acts as a link.
Can you help me to learn more?
(Other definitions for chortle that I've seen before include "Guffaw" , "Loud gleeful chuckle" , "Chuckle gleefully" , "Laugh out loud" , "Joyous chuckle" .)