Score for perfect dive secures satisfactory mark (5)
I believe the answer is:
token
'mark' is the definition.
(thesaurus)
'score for perfect dive secures satisfactory' is the wordplay.
I cannot really understand how this works, but
'satisfactory' could be 'ok' ('ok' can be similar in meaning to 'satisfactory') and 'ok' is found in the answer.
The remaining letters 'ten' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for token that I've seen before include "Sign, symbol or an evidence" , "empty gesture?" , "Nominal - souvenir" , "Voucher (for, eg, books)" , "Shopping voucher" .)