Unscrupulous

/ʌnˈskruː.pjə.ləs/ adjective medium

Lacking moral principles and willing to act dishonestly for personal gain.

The unscrupulous salesman charged elderly customers triple the fair price for basic repairs.

Memory Trick

Un- (not) plus scrupulous (careful and honest) — remove the scruples, and what's left is someone unscrupulous.