Excursion — choose to cut both ends off (6)
I believe the answer is:
picnic
'excursion' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for picnic that I've seen before include "something easy to do" , "outdoor eating" , "Alfresco repast" , "Informal outdoor summer meal" , "is difficult" .)