a negative reaction to a certain food, material, etc.
I am allergic to cat hair.

to stop working; out of order
My car broke down so I had to take the bus to work.

a light, repeated task usually done to keep a house in order
My weekly chores are taking out the garbage and mowing the lawn.

to make larger
The pupils dilate in the dark.

to officially leave or disassociate oneself from a group, organization, etc.
I decided to drop out of the club because they were not going in the direction that I thought they should.

to stop something from happening for a while
The research was interrupted when the funding ran out.

the study and science of the mind and behavior
The Austrian physician, Sigmund Freud, is generally considered to be the father of modern psychology.

in an unlucky manner
unfortunately, I don't have my credit card with me or I'd buy lunch.