/ ˈtesti; NAmE / adjective
easily annoyed or irritated
SYN irritable
► test·ily / -ɪli; NAmE / adverb :
'Leave me alone,' she said testily.
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WORD ORIGIN
late Middle English (in the sense headstrong, impetuous ): from Anglo-Norman French testif , from Old French teste head, from Latin testa shell.