flub something up

tv. to do something incorrectly; to mess up a procedure. Now don’t flub this up.

Name	Pronounced	Usage
Iwan	EE-wan (Welsh), EE-vahn (Polish)	Welsh, Polish
Dukes	[du:ks]
Zahia	-	Arabic
Islwyn	-	Welsh
Leevi	LE:-vee	Finnish
Roopertti	RO:-pert-tee	Finnish