reacts Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition verb. to respond to something or act in response. Example Sentence The mailman reacts the same way everytime the dog chases him. More Example Sentences The dog reacts when it hears a bell. Synonyms responds; replies; answers Antonyms ignores; neglects; avoids Hear It! Say It! Write It! reacts Switch to cursive Start Share with your friends: