Following inspiration after vacation, engineer passed to a high degree (2,6)
I believe the answer is:
in spades
'to a high degree' is the definition.
(I've seen this before)
'following inspiration after vacation engineer passed' is the wordplay.
'following' is a charade indicator (letters next to each other).
'after vacation' means to remove the middle letters (the inside letters must vacate).
'engineer' indicates an anagram.
'inspiration' with its centre taken out is 'in'.
'passed' with letters rearranged gives 'spades'.
'in' put next to 'spades' is 'IN SPADES'.
(Other definitions for in spades that I've seen before include "to a high degree" , "Extremely" , "how a contract may be agreed" , "Without restraint" , "Woman's garment" .)