I sat outside when ready (6)
I believe the answer is:
poised
'ready' is the definition.
(thesaurus)
'i sat outside' is the wordplay.
'sat' becomes 'posed' ('pose' can be a synonym of 'sit').
'outside' indicates putting letters inside.
'i' placed inside 'posed' is 'POISED'.
'when' is the link.
(Other definitions for poised that I've seen before include "Graceful" , "Balanced or self-confident" , "Balanced or braced" , "Elegant, self assured" , "Elegant, self-assured" .)