Go in using lever to be adventurous (12)
I believe the answer is:
enterprising
'be adventurous' is the definition.
(I've seen this before)
'go in using lever' is the wordplay.
'go in' becomes 'enter' ('enter' can be a synonym of 'go in').
'using lever' becomes 'prising'.
'enter'+'prising'='ENTERPRISING'
'to' acts as a link.
(Other definitions for enterprising that I've seen before include "Go ahead" , "Venturesome" , "Adventurous and imaginative" , "Showing initiative" , "daring" .)