Dull chore taking seconds (5)
I believe the answer is:
dusty
'dull' is the definition.
(thesaurus)
'chore taking seconds' is the wordplay.
'chore' becomes 'duty' (I've seen this in another clue).
'taking' means one lot of letters goes inside another.
'seconds' becomes 's' (abbreviation).
'duty' enclosing 's' is 'DUSTY'.
(Other definitions for dusty that I've seen before include "not cleaned thoroughly" , "bad?" , "Grubby" , "Particle-covered" , "Ms Springfield" .)