如何わしい

Etymology
Alteration from, itself derived from.

The sound shift from to  was probably influenced by the medial  in roughly synonymous adjective.

Adjective

 * 1) unreliable, doubtful, uncertain
 * 2) questionable, dubious, suspicious
 * 3) * 濃紅葉小倉色紙 (Koi Momiji Ogura no Shikishi), kabuki play; 1816:
 * 4) indecent, licentious, obscene
 * 5) disreputable, dishonest, shady
 * 1) indecent, licentious, obscene
 * 2) disreputable, dishonest, shady
 * 1) disreputable, dishonest, shady

Usage notes

 * 如何わしい implies something that cannot be trusted, or that may be immoral.
 * implies something for which the true nature or quality isn't known, but that may be good or may be bad.
 * implies something for which the true nature isn't known, and this uncertainty is a bad thing.
 * implies something for which the true nature isn't known, and this uncertainty causes one to be curious.
 * implies something suspicious that draws attention.

Synonyms

 * 信用できない: (“confidence, faith”) +  (“cannot”);