sick can be used as an adjective to describe something extraordinary, intense, or unpleasant. It can also be used to describe someone as being very ill or in bad health. It is common to hear the expression 'feeling sick' to express a feeling of nausea or an uncomfortable sensation in the body.
1. His skateboarding trick was sick!
2. He's been sick for several days with a terrible fever.
3. I'm feeling really sick—I think I'm going to throw up.
when using the word 'sick' as an adjective, be sure to consider the connotation. It should not be used to describe someone's physical or mental illness in a derogatory way. Similarly, it is not appropriate to describe someone's physical or mental disabilities as 'sick'.