1) to render one’s chances for success less likely, especially in ways that subject it to external influences;
2) to jeopardize in such a way as to cede control over the outcome
The project manager's exhausting application of his "expertise" to every minute task enchanced the projections for on-time completion.
(n.) pride derived from the act of defecating and its result, esp. if expecting other bathroom patrons to experience its sickening effects; pride that cometh after the fall (as in plop)
Leaving the stall, and noticing Joe fast on my heels to use the same, I couldn't help but hear the poobris at the back of my mind grin with a dastardly "choke on that, fucker".
The closer to the ground, hence lower, of the two anatomical features whose resident organs govern a man's decision-making; his crotch.
By metaphorical extension, a man's head is his upper house of parliament, which in some cases vetoes the ill-conceived impulses of the lower house but is can be overruled by a super majority in the lower house declaring a state of "gots-to-have-it".
A: You see that disaster Bob went home with?
B: Yuuup, he definitely let his lower house of parliament decide that one.