GMAT Vocabulary Flash Cards @ englishpdf.com and englishteststore.com File 350 inscrutable (adj) Impenetrably mysterious or profound insecure (adj) Not assured of safety insensible (adj) Imperceptible insentient (adj) Lacking the power of feeling or perceiving inseparable (adj) That can not be separated insidious (adj) Working ill by slow and stealthy means insight (n) Intellectual discernment insignificance (n) Lack of import or of importance