full butt

bust one's butt

To work exceptionally hard.

butt heads

To argue uncompromisingly.

butt in

To join a conversation or situation in which one is not welcome or invited; to interject (connotes a rude or discourteous interruption).

butt up

To touch closely, to scrape (against); to press firmly (against).

come full circle

To make a complete change or reform.

few cards shy of a full deck

Mentally deranged; demented; insane.

full blast

Maximum capacity or effort

full circle

Through a cycle of transition, returning to where one started after gaining experience or exploring other things.