1annoy someone
put/ get someone’s back up
2in one’s thoughts subconsciously
at the back of one’s mind
3stop annoying someone
get off one’s back
4know something well
know a place like the back of one’s hand
5work very hard
put one’s back into
6betray
stab someone in the back
7retaliate
get one’s own back
8refuse/ reject
turn one’s back on
9you help me and i’ll help you
you scratch my back and i’ll scratch yours
10isolated place
the back of beyong
11in bed due to illness
on one’s back