Diligently ignoring timeline in order to be flexible (8)
I believe the answer is:
yielding
'flexible' is the definition.
('yielding' can be similar in meaning to 'flexible')
I don't understand the rest of the clue.
(Other definitions for yielding that I've seen before include "Submissive" , "compliant" , "Ceding, conceding" , "Producing, delivering" , "Capitulating" .)