(adj): tough and callous by virtue of experience
(adj): facing facts or difficulties realistically and with determination
(adj): very difficult; severely testing stamina or resolution
(adj): vs. easy), hard -- (not easy; requiring great physical or mental effort to accomplish or comprehend or endure
(adj): vs. tender), toughened -- (physically toughened
(adj): having calluses; having skin made tough and thick through wear
(adj): made tough by habitual exposure
(adj): tanned and coarsened from being outdoors
(adj): substantially made or constructed
(adj): vs. delicate) -- (sturdy and strong in constitution or construction; enduring
(adj): violent and lawless
(adj): vs. nonviolent) -- (acting with or marked by or resulting from great force or energy or emotional intensity
(adj): feeling physical discomfort or pain (`tough' is occasionally used colloquially for `bad')
(adj): vs. comfortable) -- (providing or experiencing physical discomfort
(adj): vs. tender) -- (resistant to cutting or chewing
(adj): difficult to chew
(adj): requiring much chewing
(adj): resembling or made to resemble leather; tough but pliable
(adj): (of meat) full of sinews; especially impossible to chew
(adj): having or resembling fibers especially fibers used in making cordage such as those of jute
(adj): having a relatively tough outer covering
(adj): unfortunate or hard to bear
(adj): vs. good) -- (having undesirable or negative qualities
(adj): making great mental demands; hard to comprehend or solve or believe
(adj): vs. easy), hard -- (not easy; requiring great physical or mental effort to accomplish or comprehend or endure
(n): someone who learned to fight in the streets rather than being formally trained in the sport of boxing
(n): someone who fights (or is fighting)
(n): an aggressive and violent young criminal
(n): someone who has committed a crime or has been legally convicted of a crime
(n): a cruel and brutal fellow
(n): someone who attacks
One tough cucumber.