Argos supply entertaining new donatable items (6)
I believe the answer is:
organs
'donatable items' is the definition.
I can't tell whether this defines the answer.
'argos supply entertaining new' is the wordplay.
'supply' is an anagram indicator (in a supple way).
'entertaining' means one lot of letters goes inside another (inviting in, as for dinner).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'argos' is an anagram of 'orgas'.
'orgas' enclosing 'n' is 'ORGANS'.
Can you help me to learn more?
(Other definitions for organs that I've seen before include "Functional parts of the body, or musical instruments" , "newspapers" , "Groans over distinct parts of animal body" , "Functional units in the body" , "Periodicals published by special interest groups" .)