Go very quietly out East (3)
I believe the answer is:
pep
'go' is the definition.
(thesaurus)
'very quietly out east' is the wordplay.
'very quietly' becomes 'pp'.
'out' indicates putting letters inside.
'east' becomes 'e' ('E' can be a synonym of 'east').
'pp' going around 'e' is 'PEP'.
(Other definitions for pep that I've seen before include "Energy, zip" , "Energy or enthusiasm" , "Palindromic vim and vigour" , "Go" , "Energy, liveliness" .)