11 letters · 18 points in Scrabble
adjective fit to be certified as insane (and treated accordingly)
adjective capable of being guaranteed or certified
originEtymology tree English certify Proto-Indo-European *-tḗr Proto-Indo-European *-dʰlom Proto-Indo-European *-dʰlis Proto-Italic *-ðlis Latin -bilis Latin -ābilis Old French -ablebor. Middle English -able English -able English certifiable From certify + -able.
Etymology from Wiktionary, CC BY-SA 3.0