Definition of ptui in English:
ptui
(also ptooey)
exclamation p(ə)ˈtuːiˈtuːi
Representing the sound of a person spitting; (hence) expressing disgust or contempt: ‘Pah!’ ‘Pshaw!’.
Origin
1930s. Imitative. Compare pfui, phooey, and also ptish, pshaw, etc.