Fines stopping chaotic Tube strike (6)
I believe the answer is:
buffet
'strike' is the definition.
(I know that buffet is a more specific form of the action strike)
'fines stopping chaotic tube' is the wordplay.
'fines' becomes 'ff' (an abbreviation for fine written twice).
'stopping' means one lot of letters goes inside another (stopping can mean blocking a gap).
'chaotic' is an anagram indicator.
'tube' anagrammed gives 'buet'.
'ff' placed within 'buet' is 'BUFFET'.
(Other definitions for buffet that I've seen before include "beat" , "Self-service meal; strike" , "cold meats, etc." , "Light refreshments - strike" , "Self-service meal - pound" .)