二楼已经说的比较全了，补充一点，guest 表示顾客时通常用于宾馆，饭店。 关于slug 和 hit : If you slug someone, you hit them hard. 而且slug 表示“打”时是非正式的用法。 关于 handle 和deal with: Handel often suggests control and calmness. It is often used to talk about whether people are capable of handling or can handle a situation. Deal with sth is usually used in more businesslike situations. It is often used to discuss ways, methods and means of dealing with problems.（牛津英语同义词学习词典）

customer and client have the same meaning, but customer is someone who buy something from a store. Client is someone who receive a service from a lawyer or a company consumer is a more generic word, anyone who consume something is a consumer. guest is someone who is invited to visit a home or take part in an event. Guest is not synonym of client or customer. A guest don´t buy anything and don´t receive any service, he goes to a place because he was invited. Otherwise a customer is not invited to go anywhere, it´s a commercial relationship, a guest doesn´t have a commercial relationship. It´s impossible to confuse this two words.

customers/clients/consumers/guest are essentially all synonyms. It is the same with slug/hit and "Let me handle it/Let me deal with it". The usage depends on the choice of the individual speaker.