Speed of work was satisfying, just about (5)
I believe the answer is:
tempo
'speed' is the definition.
(I've seen this before)
'work was satisfying just about' is the wordplay.
'work' becomes 'op' (abbreviation for opus).
'was satisfying' becomes 'met' (satisfied or met conditions).
'just about' says the letters should be written backwards (turned about or around).
'op'+'met'='opmet'
'opmet' in reverse letter order is 'TEMPO'.
'of' acts as a link.
(Other definitions for tempo that I've seen before include "Speed of a musical piece" , "Muscial time" , "Speed at which piece of music is played" , "Speed of 3A" , "musical quality?" .)