mental exhaustion mental energy • mental faculty · · · Info · Definitions · Synonyms · Characters · · mental exhaustion · · Text Common · · Latin · · Scripts 17 · · Length 6 · · Syllables Definitions · · · (noun) exhaustion that affects mental keenness. Synonyms: mental exhaustion, brain-fag. · · Noun Definition 1 Synonyms · · · brain-fag · · Synonym 1 Characters · · space U+0020 a latin small letter a U+0061 e latin small letter e U+0065 h latin small letter h U+0068 i latin small letter i U+0069 l latin small letter l U+006C m latin small letter m U+006D n latin small letter n U+006E o latin small letter o U+006F s latin small letter s U+0073 t latin small letter t U+0074 u latin small letter u U+0075 x latin small letter x U+0078