Spanish trained killer boring, humdrum, a tad ordinary (7)
I believe the answer is:
matador
'spanish trained killer' is the definition.
'matador' can be an answer for 'killer' (I've seen this before). I also know that 'spanish' relates to this answer.
'boring humdrum a tad ordinary' is the wordplay.
'boring' indicates a hidden word (the solution has bored or cut into the clue).
'MATADOR' can be found hidden inside 'humdrum a tad ordinary'.
Can you help me to learn more?
(Other definitions for matador that I've seen before include "he aims to get a bull" , "The one who kills the bull" , "who does for bulls" , "Bullfighter who slays the bull" , "paid killer" .)