Caustic (adjective)

1. Capable of burning or corroding organic tissue by chemical action.
2. Sarcastic or bitter in a way that is hurtful and cruel.
3. Severely critical or biting in nature.

Origin:

Mid 17th century: from latin causticus, from greek kaustikos "burning", from kaiein "to burn".

Examples:

1. The chemical was caustic and caused severe burns on contact.
2. The caustic comment made her feel embarrassed.
3. The worker handled the caustic chemicals with great care.
4. The caustic wit of the comedian was appreciated by the audience.
5. The caustic remark was not taken kindly by the audience.