It's said girl tricked a large reptile (8)
I believe the answer is:
anaconda
'large reptile' is the definition.
(I've seen this before)
'it's said girl tricked a' is the wordplay.
I cannot quite understand how this works, but
'girl' could be 'con' and 'con' is found within the answer.
'a' could be 'an' and 'an' is found within the answer.
The remaining letters 'ada' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for anaconda that I've seen before include "One may put squeeze on" , "1 of 21 [SNAKES]" , "Water-boa" , "Large semiaquatic snake" , "crawler" .)