Example : He deserves a good kick in the butt.
Are you going to sit on your fanny and do nothing?.

Synonyms : arse, ass, backside, bottom, bum, buns, butt, buttocks, can, derriere, fanny, fundament, hind end, hindquarters, keister, nates, posterior, prat, rear, rear end, rump, seat, stern, tail, tail end, tooshie, tush

Example : Behind by two points.
The 8th inning found the home team trailing.

Example : He followed behind.
Seen from behind, the house is more imposing than it is from the front.
The final runners were far behind.

Example : When he died he left much unfinished work behind.
Left a large family behind.
The children left their books behind.
He took off with a squeal of tires and left the other cars far behind.

Example : The clock is almost an hour slow.
My watch is running behind.

Synonyms : slow

Example : Fell behind in his studies.
Their business was lagging behind in the competition for customers.

Example : He fell behind with his mortgage payments.
A month behind in the rent.
A company that has been run behindhand for years.
In arrears with their utility bills.

Synonyms : behindhand, in arrears