A Celt is unusually ready to give! (7)
I believe the answer is:
'ready to give' is the definition.
I can't judge whether this defines the answer.
'a celt is unusually' is the wordplay.
'unusually' indicates anagramming the letters.
'aceltis' is an anagram of 'ELASTIC'.
Can you help me to learn more?
(Other definitions for elastic that I've seen before include "Tape containing flexible rubber" , "Scale it (anag.)" , "Material that stretches" , "Stretching tape" , "Resilient" .)