Off sick, not available (2,5)
I believe the answer is:
in stock
'available' is the definition.
(similar in meaning)
'off sick not' is the wordplay.
'off' indicates anagramming the letters.
'sick'+'not'='sicknot'
'sicknot' is an anagram of 'IN STOCK'.
(Other definitions for in stock that I've seen before include "available" , "On the shelf" , "Where one may have cooked any meat" , "Held by a shop" .)