Euler is prepared for retirement (7)
I believe the answer is:
leisure
'retirement' is the definition.
(I've seen this before)
'euler is prepared' is the wordplay.
'prepared' indicates an anagram.
'euler'+'is'='euleris'
'euleris' is an anagram of 'LEISURE'.
'for' acts as a link.
(Other definitions for leisure that I've seen before include "Free-time" , "Period of relaxation" , "Time when not working" , "Freedom from work" , "Recreation time" .)