See the obvious, though it's not meant to be seen (6)
I believe the answer is:
covert
'it's not meant to be seen' is the definition.
I can't tell whether this defines the answer.
'see the obvious' is the wordplay.
'see' becomes 'C' (the word for the letter, according to Chambers).
'the obvious' becomes 'overt' (I've seen this before).
'c'+'overt'='COVERT'
'though' acts as a link.
Can you help me to learn more?
(Other definitions for covert that I've seen before include "Undercover, secret" , "Hidden, secret" , "Hidden - thicket" , "Concealed - flock of coots" , "Concealed, hidden" .)