Toughened after time with permanent post (7)
I believe the answer is:
tenured
'permanent post' is the definition.
Both the answer and definition are adjectives. Perhaps there's a link between them I don't understand?
'toughened after time' is the wordplay.
I cannot really see how this works, but
'time' could be 'ten' (I've seen this before) and 'ten' is found in the answer.
This may be the basis of clue (or it may be nonsense).
'with' is the link.
Can you help me to learn more?
(Other definitions for tenured that I've seen before include "Unlikely to be removed from office" , "with a job for life?" , "Holding a permanent post" , "having secure job" .)