Break into an untried arrangement (7)
I believe the answer is:
intrude
'break' is the definition.
(I know that intrude is a more specific form of the action break)
'an untried arrangement' is the wordplay.
'arrangement' is an anagram indicator.
'untried' is an anagram of 'INTRUDE'.
'into' acts as a link.
(Other definitions for intrude that I've seen before include "Stick one's nose in" , "Because of temperature, blue" , "Gatecrash" , "Enter uninvited and unwelcome" , "Push in where not wanted" .)