Go in hope, possibly (3)
I believe the answer is:
pep
'go' is the definition.
(I've seen this before)
'in hope possibly' is the wordplay.
'in' says the answer is hidden in the clue.
'PEP' is hidden within 'hope possibly'.
(Other definitions for pep that I've seen before include "Ginger; tax-free investment" , "Energy, zip" , "savings plan" , "Palindrome for vitality or energy" , "Energy or enthusiasm" .)