Explosive gets dropped regularly in commotion (7)
I believe the answer is:
torpedo
'explosive' is the definition.
(I've seen this before)
'dropped regularly in commotion' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'in' indicates putting letters inside.
'commotion' becomes 'todo' (synonyms).
The alternate letters of 'dropped' are 'rpe'.
'rpe' going within 'todo' is 'TORPEDO'.
'gets' is the link.
(Other definitions for torpedo that I've seen before include "Sea-borne missile" , "Missile form a submarine" , "Trooped (anag.)" , "fish you want" , "Explosive underwater weapon" .)