Nice latch, terribly complicated (9)
I believe the answer is:
technical
'complicated' is the definition.
(thesaurus)
'nice latch terribly' is the wordplay.
'terribly' indicates an anagram.
'nice'+'latch'='nicelatch'
'nicelatch' with letters rearranged gives 'TECHNICAL'.
(Other definitions for technical that I've seen before include "sort of college" , "Concerned with applied science" , "Requiring special knowledge to be understood" , "Using specialised skill" , "Concerned with applied sciences" .)