decades-long Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition adjective. lasting for a period of many years. Example Sentence The team's decades-long effort finally paid off with a championship victory. More Example Sentences They had a decades-long friendship. Synonyms long-lasting; enduring; prolonged Antonyms short-lived; brief; temporary Hear It! Say It! Write It! decades-long Switch to cursive Start Share with your friends: