Entry 3 senses · 2 variants Webster, 1913 frustrating · IPA /ˈfɹʌsˌtɹeɪ̯tɪŋ/ n. adj. 01 n. an act of hindering someone's plans or efforts. 1. an act of hindering someone's plans or efforts. Syn. frustration, thwarting, foiling. 02 adj. preventing realization or attainment of a desire; causing frustration. 1. preventing realization or attainment of a desire; causing frustration. 2. discouraging. Opposite of encouraging. Syn. frustrative, thwarting. — Syn. -- disappointing.