Yearning for zero - staff has no time (8)
I believe the answer is:
lovesick
'staff has no time' is the definition.
I can't judge whether this defines the answer.
'yearning for zero' is the wordplay.
'yearning' becomes 'sick' (I can't explain this - if you can you should give a lot more credence to this answer).
'for' is a charade indicator (letters next to each other) (I've seen this in other clues).
'zero' becomes 'love' (love is zero in tennis).
'sick' after 'love' is 'LOVESICK'.
Can you help me to learn more?
(Other definitions for lovesick that I've seen before include "Nauseatingly infatuated?" , "Pining for one's sweetheart" .)