sine qua non

Sine qua non can be translated literally as "Without which, not". Though this may sound like gibberish, it means more or less "Without (something), (something else) won't be possible". Sine qua non sounds slightly literary, and it shouldn't be used just anywhere. But it actually shows up in many contexts, including business ("A solid customer base is the sine qua non to success"), show business ("A good agent is a sine qua non for an actor's career"), and politics ("His support was really the sine qua non for her candidacy").