shadfly Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition noun. a type of insect related to mayflies. Example Sentence The shadfly landed on the water. More Example Sentences A shadfly can be seen in summer. Synonyms mayfly; insect Antonyms none; no antonyms Hear It! Say It! Write It! shadfly Switch to cursive Start Share with your friends: