A thief's attempted robbery of an Mohawk Road East pharmacy was foiled when an 18-year-old cashier ignored his warning that he had a gun.

Hamilton police Sergeant Terri Collings said the young woman had just taken the cash tray out of her register when the man entered the Shopper's Drug Mart by the corner of Upper Ottawa Street at about 10:40 p.m. on Sunday evening.

Though he brandished what appeared to be a gun, the woman was convinced it was a fake and walked away. The thief fled.

Sgt. Collings said although the cashier thwarted the robbery, she potentially endangered her own life by not turning over the money and calling police after the thief left.

"It easily could have gone another way," she said. "We always encourage people to not try taking matters in their own hands."

The suspect is described as white, 20 years old, between five feet 10 inches and six feet tall, with a stocky build.

He was wearing dark, rapper-style WRG pants with a belt and a black hoodie that covered his face. He also sported a backpack with a white design on front.