Go up a second time (3)
I believe the answer is:
pep
'go' is the definition.
(both can mean energy or vitality)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for pep that I've seen before include "Palindrome for vigour" , "Ginger; tax-free investment" , "Palindrome for vitality or energy" , "Go" , "savings plan" .)