Strong material rejected after check (10)
I believe the answer is:
determined
'strong' is the definition.
(similar in meaning)
'material rejected after check' is the wordplay.
'material' becomes 'denim' (type of fabric).
'rejected' says the letters should be written backwards.
'after' says to put letters next to each other.
'check' becomes 'deter' (slow the progress of).
'denim' in reverse letter order is 'mined'.
'mined' put after 'deter' is 'DETERMINED'.
(Other definitions for determined that I've seen before include "With full strength and concentration" , "Found out" , "set" , "settled" , "Decided - resolute" .)