A person who preforms manual labor in the oilfields, typically in a drilling capacity. Can be onshore or offshore. Personnel who work in the oilfields but are not involved with drilling are not true roughnecks. Roughnecks are know for their perverted sense of humor, frequent cussing, high pay, and as being some of the hardest working folks you'll ever know. Roughnecks can be oilfield-trash but not all of them are.
Look at those Roughnecks over yonder trippin' that string. Look at those boys go!
An uncouth, low IQ, blue-collar worker making more money than the average starting physician, lawyer, or engineer, yet nothing to show for it, unless it's a monster truck or double-wide trailer because they spend most of their money on booze and women. Most of them live on the Texas or Louisiana coast and Alaska's Mat-Su Valley when they aren't working. Roughneck women that work in those oilfield environments often have a chip on their shoulder and distrust or dislike of men that are kind, intelligent, or courteous.