to be secretly happy, especially because you have played a trick on someone or criticized them without them knowing
WORD FOCUS: laugh WORD FOCUS: laugh giggleto laugh repeatedly in a silly way because you are amused, embarrassed, or nervous sniggerto laugh unkindly and quietly, especially at something that is not meant to be funny chuckleto laugh quietly, especially because you are thinking about something funny roar/howl with laughterto laugh very loudly because you think something is very funny be in hystericsto laugh uncontrollably crack upinformalto suddenly start laughing a lot
laugh at somebody/something
1to make unkind or funny remarks about someone, because they have done or said something you think is stupid [= tease]:
I'm afraid the other kids will laugh at me because I don't understand.
2to seem not to care about something that most people would worry about:
Young offenders just laugh at this sort of sentence.
laugh something ↔ off
to pretend that something is less serious than it really is by laughing or joking about it:
Knox laughed off rumors that he would be running for mayor.
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.