Pace office worker before starting others (5)
I believe the answer is:
tempo
'pace' is the definition.
('tempo' can be a synonym of 'pace')
'office worker before starting others' is the wordplay.
'office worker' becomes 'temp' (I've seen this before).
'before' means one lot of letters go next to another.
'starting' indicates taking the first letters.
The first letter of 'others' is 'o'.
'temp'+'o'='TEMPO'
(Other definitions for tempo that I've seen before include "Pace of a piece of music" , "Rhythm of piece of music" , "Speed of a musical piece" , "Cadence" , "Rhythm, metre" .)