# adjective. - (of a substance or object) strong enough to withstand adverse conditions or rough or careless handling. * tough backpacks for climbers - able to endure hardship or pain. * even at this ripe old age, he's still as tough as old boots - demonstrating a strict and uncompromising attitude or approach. * police have been getting tough with drivers - (of a person) strong and prone to violence. * tough young teenagers