Strained, being annoyed about demand after vacation (7)
I believe the answer is:
riddled
'strained' is the definition.
(riddling is a kind of straining)
'annoyed about demand after vacation' is the wordplay.
'annoyed' becomes 'riled' ('rile' can be a synonym of 'annoy').
'about' is an insertion indicator.
'after vacation' means to remove the middle letters (the inside letters must vacate).
'demand' with its centre removed is 'dd'.
'riled' going around 'dd' is 'RIDDLED'.
'being' acts as a link.
(Other definitions for riddled that I've seen before include "didn't talk plainly" , "Pierced with many holes as by tommygun" , "Spread throughout" , "screened" , "spoken obscurely" .)