Sketch crocodile for opening (7)
I believe the answer is:
profile
'sketch' is the definition.
(thesaurus)
'crocodile for opening' is the wordplay.
'crocodile' becomes 'file' (I can't justify this - if you can you should give a lot more credence to this answer).
'for' becomes 'pro' (as in being 'pro' or in favour of something).
'opening' says to put letters next to each other (some letters appear before or 'open' others).
'file' after 'pro' is 'PROFILE'.
Can you help me to learn more?
(Other definitions for profile that I've seen before include "In which one may be photographed" , "Side view; portrait in words" , "record" , "Sideways outline" , "image" .)