IT end working with MS Outlook (7)
I believe the answer is:
mindset
'outlook' is the definition.
(I know that outlook can be written as mindset)
'it end working with ms' is the wordplay.
'working with' indicates anagramming the letters (working with the letters).
'it'+'end'='itend'
'itend' mixed up with 'ms' gives 'MINDSET'.
(Other definitions for mindset that I've seen before include "Outlook" , "fixed attitude" , "Characteristic mental attitude" , "way of thinking" , "attitudes and values" .)