Surprisingly, age is no worry (7)
I believe the answer is:
agonise
'worry' is the definition.
(I've seen this before)
'surprisingly age is no' is the wordplay.
'surprisingly' indicates an anagram.
'age'+'is'+'no'='ageisno'
'ageisno' is an anagram of 'AGONISE'.
(Other definitions for agonise that I've seen before include "Suffer great pain over something" , "Labour" , "Worry intensely" , "worry a lot" , "Torment oneself" .)