1.
If you shake off something that you do not want such as an illness or a bad habit, you manage to recover from it or get rid of it.
Businessmen are trying to shake off habits learned under six decades of a protected economy...
He was generally feeling bad. He just couldn’t shake it off.
PHRASAL VERB : V P n (not pron) , V n P
2.
If you shake off someone who is following you, you manage to get away from them, for example by running faster than them.
I caught him a lap later, and although I could pass him I could not shake him off...
He was unaware that they had shaken off their pursuers.
PHRASAL VERB : V n P , V P n (not pron)
3.
If you shake off someone who is touching you, you move your arm or body sharply so that they are no longer touching you.
He grabbed my arm. I shook him off...
She shook off his restraining hand.
PHRASAL VERB : V n P , V P n (not pron)