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 boysgo!