tough

Dictionary definition · tough

someone who learned to fight in the streets rather than being formally trained in the sport of boxing
an aggressive and violent young criminal
a cruel and brutal fellow

not given to gentleness or sentimentality"a tough character"
very difficult; severely testing stamina or resolution"a rugged competitive examination"
physically toughened"the tough bottoms of his feet"
substantially made or constructed"sturdy steel shelves"
violent and lawless"the more ruffianly element"
feeling physical discomfort or pain (‘tough’ is occasionally used colloquially for ‘bad’)"my throat feels bad"
resistant to cutting or chewing
unfortunate or hard to bear"had hard luck"
making great mental demands; hard to comprehend or solve or believe"a baffling problem"

Source: Open English WordNet (CC BY 4.0).