Interrupt, but you start getting used to it (5,2)

I believe the answer is:
break in
'interrupt' is the definition.
(breaking in is a kind of interrupting)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for break in that I've seen before include "Illegally enter" , "Enter forcibly" , "Domesticate" , "Forced entry" , "Interrupt - burglary" .)
