interj. [ Of imitative origin. ] Pish! pooch! -- an exclamation used as an expression of contempt, disdain, dislike, etc. [ Written also psha. ] [ 1913 Webster ]

v. i. To express disgust or contemptuous disapprobation, as by the exclamation “ Pshaw!” [ 1913 Webster ]

The goodman used regularly to frown and pshaw wherever this topic was touched upon. Sir W. Scott. [ 1913 Webster ]