Inspiration from cleaner at office (5)
I believe the answer is:
erato
'inspiration' is the definition.
(one of the muses in Greek mythology)
'from cleaner at office' is the wordplay.
'from' indicates the answer is hidden within the clue.
'ERATO' is hidden in the letters of 'cleaner at office'.
(Other definitions for erato that I've seen before include "Arts patron" , "One inspiring" , "Who may have inspired poetry" , "Poet's muse" , "poetical inspiration" .)