It doesn't just mean that Kojak actor (5)
I believe the answer is:
telly
'mean that kojak actor' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'it doesn't' is the wordplay.
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'doesn't' becomes 'elly' (I can't explain this - if you can you should believe this answer much more).
't'+'elly'='TELLY'
'just' acts as a link.
Can you help me to learn more?
(Other definitions for telly that I've seen before include "Television" , "'The box' (colloquial)" , "Familiar name for TV" , "- - Savalas" , "cop in seventies" .)