Someone who's super
petty; a low-level hustler or thief who only goes after small dollars; a nickel-and-dimeing businessperson.
"That nickelrat is always trying to borrow two dollars from me."
"That's the third time that nickelrat at the market tried to short change me."
"That nickelrat had the nerve to say "let's split the check" after HE asked ME out."
