Walmartish

In regards to business or personal endeavors: being shady, underhanded, inconsiderate, or sleezy.
Also: not on the up and up.
Antonyms: respectable; considerate; moral; ethical; honest; straightforward

That Walmartish guy down the street keeps letting his dog poop in my yard without cleaning it up.

It was very Walmartish of that guy at the party last night to just take my beer without asking.