A hypochondriac is a person who constantly worries about their health and believes they have serious medical conditions, even when there is no evidence to support it. They may exaggerate or misinterpret normal bodily sensations as signs of illness.
Example: Sarah is a hypochondriac because she often feels a minor headache and automatically thinks she has a brain tumor.
Very Simple Definition:
A hypochondriac is someone who thinks they are always sick, even if they are not. They worry a lot about their health.
Example: Tom is a hypochondriac because he always thinks he is going to get a cold, even when everyone else is healthy.