Back

[I’ll] be right back

a pat on the back

a slap on the back

a while back/ago

After saying he agreed to the terms, he tried to back out by making a lot of conditions

an encouraging pat on the back

at the back of beyond

back and forth

Back me or sack me!

Back off!

back scuttle

back to basics

back to front

back to the grind

Back up a little!