Shaggy wasted hours getting to grips with new number (7)
I believe the answer is:
unshorn
'shaggy' is the definition.
(thesaurus)
'wasted hours getting to grips with new number' is the wordplay.
'wasted' indicates anagramming the letters.
'getting to grips with' means one lot of letters goes inside another (one group of letters grips another).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'number' becomes 'n' (n can represent any number).
'hours' is an anagram of 'ushor'.
'ushor' placed around 'n' is 'unshor'.
'unshor'+'n'='UNSHORN'
(Other definitions for unshorn that I've seen before include "Of hair or wool, not cut" , "still having woollen coat on" .)