Witness briefly inspired by encouraging gesture proceeded carefully (5)
I believe the answer is:
nosed
'proceeded carefully' is the definition.
(to nose along is to move along slowly)
'witness briefly inspired by encouraging gesture' is the wordplay.
'witness' becomes 'see' (synonyms).
'briefly' means to remove the last letter.
'inspired by' means one lot of letters goes inside another (some letters breathed in or 'inspired' by others).
'encouraging gesture' becomes 'nod' (nod is a kind of gesture. I am not sure about the 'encouraging' bit.).
'see' with its final letter removed is 'se'.
'se' going within 'nod' is 'NOSED'.
Can you help me to learn more?
(Other definitions for nosed that I've seen before include "Moved slowly and cautiously forward" , "Pried" , "edged out" , "Move back or away" , "Beginner" .)