Ginx is likely misspelled.

Ginx has no English definition.

As a noun jinx

is a hex; an evil spell.

As a verb jinx

is to cast a spell on.

As an interjection jinx

is used after the same response is said by two people simultaneously. Often, a game is played where the person who failed to say "jinx" first becomes "jinxed", whereby they cannot speak until someone says their name.