Tied up at work facility (8)
I believe the answer is:
aptitude
'facility' is the definition.
(thesaurus)
'tied up at work' is the wordplay.
'work' indicates an anagram.
'tied'+'up'+'at'='tiedupat'
'tiedupat' is an anagram of 'APTITUDE'.
(Other definitions for aptitude that I've seen before include "faculty" , "Update it, having a relevant talent" , "Update it, having natural skill" , "A particular talent or facility" , "capacity" .)