1 : to allow (something that is bad, unpleasant, etc.) to exist, happen, or be done
Our teacher will not tolerate bad grammar.
Racist or sexist behavior will not be tolerated.
I can't tolerate that noise.
2 : to experience (something harmful or unpleasant) without being harmed
These plants tolerate drought well.
3 : to accept the feelings, behavior, or beliefs of (someone)
I don't like my boss, but I tolerate him.