Synonyms and related words :
distasteful, doubtable, doubtful, dubious, dubitable, hardly possible, implausible, improbable, inappropriate, inauspicious, inconceivable, incredible, more than doubtful, objectionable, questionable, remote, unacceptable, unattractive, unbecoming, uncongenial, unfit, unfitting, unimaginable, unpromising, unpropitious, unseemly, unsuitable, unthinkable