fantasising Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition verb. to create or imagine in a fantasy; have daydreams about Chiefly British. Example Sentence He is fantasising when he says he plans to start his own company. Synonyms imagine; conceive of; ideate; envisage Antonyms reality Hear It! Say It! Write It! fantasising Switch to cursive Start Share with your friends: