To terminate the employment of a worker, often temporarily, due to economic conditions or lack of work. The company had to lay off several employees due to the downturn in the market.
To stop doing or using something, often as a form of restraint or moderation. You should lay off the junk food if you want to lose weight.
To stop bothering or criticizing someone. I wish you would lay off me about my grades; I'm doing my best.