Entry 1 sense Webster, 1913 Guarantor /gĕrˌ-ən-tôr'/ · Guar·an·tor · IPA /ˈɡæɹəntə(ɹ)/ 01 n. One who makes or gives a guaranty; a warrantor; a surety. 1. One who makes or gives a guaranty; a warrantor; a surety.(Law)