The last ictodosaur, somewhat resilient (7)
I believe the answer is:
elastic
'resilient' is the definition.
(similar in meaning)
'the last ictodosaur somewhat' is the wordplay.
'somewhat' indicates a hidden word.
'ELASTIC' is hidden in the letters of 'the last ictodosaur'.
(Other definitions for elastic that I've seen before include "Springing back to shape after stretching" , "Narrow band of rubber" , "Giving" , "Resilient" , "Like a small band" .)