Lacking confidence (6)
'lacking confidence' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for insecure that I've seen before include "Not firmly fixed" , "Fearful, unsafe." , "safe? Hardly" , "Not adequately protected" , "Timid" .)
'lacking confidence' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for unsure that I've seen before include "Far from certain" , "self-confidence" , "Not certain or decided" , "Lacking confidence" , "Not certain, somewhat confused" .)