Is Grueling An Adjective Or Adverb?

Is Grueling An Adjective Or Adverb? GRUELING (adjective) American English definition and synonyms | Macmillan Dictionary. Is grueling a noun or adjective? grueling adjective – Definition, pictures, pronunciation and usage notes | Oxford Advanced American Dictionary at OxfordLearnersDictionaries.com. What part of speech is the word grueling? part of speech:adjective definition: very tiring or difficult. The