wacky

stupid, crazy, (but not necessarily bad)

Example:

That new TV comedy is really wacky, but I love it!

walk-in

a customer who enters a shop or business from the street

Example:

There is no walk-in business here. No-one likes this part of town.

walk on thin ice

to be in an unsafe position

Example:

Be careful, you're walking on thin ice. The boss hates it when people say his ideas are impractical.

walkover

an easy victory, or thing to do

Example:

This product is too expensive. Selling it will be no walkover.

wall-to-wall

comprehensive, total

Example:

His enthusiam is wall-to-wall. We'll get the contract, I'm sure.