Master the word " GRUMPY " in English: definitions, translations, synonyms, pronunciations, examples, and grammar insights - all in one complete resource. Discover the meaning , usage, and significance of Grumpy . Expand your vocabulary with in-depth insights on this important concept. Grumpy definition: surly or ill-tempered ; discontentedly or sullenly irritable; grouchy.. See examples of GRUMPY used in a sentence. GRUMPY meaning : 1. easily annoyed and complaining: 2. easily annoyed and complaining: 3. being in a slightly…. Learn more.