Accept too readily, obvious sign of age (9)
I believe the answer is:
overtrust
'accept too readily' is the definition.
I can't judge whether this defines the answer.
'obvious sign of age' is the wordplay.
'obvious' becomes 'overt' (similar in meaning).
'sign of age' becomes 'rust' (I've seen this in another clue).
'overt'+'rust'='OVERTRUST'
Can you help me to learn more?
(Other definitions for overtrust that I've seen before include "Rely too much on" , "Hope too much" , "Believe too much" .)