Hasard spielen — To play hazard. The Duden explains it as being reckless and careless, and putting one’s luck at stake.
das Hasardspiel — The game of hazard. Its second meaning in the Duden is an undertaking in which someone stakes everything without regard for others or for himself. The Duden’s example is das Hasardspiel der Generäle, the generals’ game of hazard.
der Hasardeur — The man who plays it. Among the synonyms, the Duden lists Glücksritter, a knight of fortune, and Abenteurer, adventurer.
waghalsig — Daring to the point of danger. In the Duden’s words, it describes someone who does not shy away from dangers and risks, but often pays too little attention to them in a reckless way.
Übermut tut selten gut. — High spirits seldom do good. The Duden defines Übermut as exuberance that shows itself in reckless, wanton behavior. The proverb first referred to the older meaning of the word, arrogance.
Hochmut kommt vor dem Fall. — Pride comes before a fall. The saying comes from the Book of Proverbs in the Old Testament.