ruthless
ROOTH-lisadjMeaning showing no pity; willing to hurt others to get one’s way
Memory hook RUTH = pity: RUTH-LESS. Ruth is an old word for pity. The cartoon king who takes the farmers’ very last pears has no ruth at all: he is ruthless.
Lin is a ruthless checkers player who never lets anyone take back a move.
In context The new owner was ruthless: he closed the beloved bakery, let every worker go without warning and never once looked back.
Similar merciless, pitiless, heartless, cruel
Opposite merciful, humane, compassionate
From the old word ruth, “pity,” + -less: without pity.