Almost ooze confidence (6)
I believe the answer is:
secret
'confidence' is the definition.
(I've seen this before)
'almost ooze' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'ooze' becomes 'secrete' (secreting is a kind of oozing).
'secrete' with its last letter removed is 'SECRET'.
(Other definitions for secret that I've seen before include "Hidden; unknown" , "Cloak-and-dagger" , "Confidence" , "Confidential (information)" , "away from scrutiny" .)