Main Entry: un·sound

Pronunciation: \-ˈsau̇nd\

Function: adjective

Date: 14th century

: not sound: as a : not healthy or whole <an unsound horse> b : not mentally normal : not wholly sane <of unsound mind> c : not firmly made, placed, or fixed <structurally unsound> d : not valid or true : invalid, specious <unsound beliefs>

— un·sound·ly \-ˈsau̇n(d)-lē\ adverb