It's defined as, "A feeling of self-assurance arising from one's appreciation of one's own abilities or qualities."
In football, it's often defined in one word. Success.
And for Landry Jones, the two went hand-in-hand in 2015.
After spending his first two seasons as the Steelers' third-string quarterback, Jones saw action last season when injuries mounted at the position. He played in seven games, starting two, and gaining valuable experience and even more importantly, confidence.
"The playing time gave him that and he had some success also," said quarterbacks coach Randy Fichtner. "Success breeds that. Opportunity does too. He has taken advantage of that. His confidence level is very high right now."
Jones first two seasons were typical of many young quarterbacks coming into a situation where two veterans exist. Ben Roethlisberger was cemented as the starter, and Bruce Gradkowski the solid backup. That meant Jones had to bide his time.
"It's not an easy role, but he has found a way to stay sharp," said Fichtner. "All of the backup quarterbacks I have worked with that have had success are preparing like a starter. We don't treat them any different. He is preparing that way every week.
"That is the job. He does a great job preparing throughout the week. Mental reps on the field. A lot of reps in the classroom. It's not easy, but that is the job and he's done a nice job of it. There are 32 starters and a handful of backups. He has his role, he understands his role and prepares like he is a starter."
That preparation came in handy last year. Gradkowski was injured in the preseason and lost for the year. The team signed Mike Vick to be Roethlisberger's back up, and all seemed well. Until injuries hit. Roethlisberger missed four games and five starts, Vick was injured, and suddenly Jones was at the helm.
"He has gotten a lot more mature in the offense," said Fichtner. "He is more knowledgeable. He has had play reps and it's starting to show on the practice field. He has pretty good command of the huddle. Right now he is doing a good job.
"His decision making has improved. His timing. He is getting the ball out very well. He is protecting the football, in drill work and in the team group work accuracy. Ball placement, things like that have improved every year."
Where Jones will be in the pecking order when the season starts is something not yet known. Gradkowski, who was an unrestricted free agent, is back after re-signing with the team. Second-year quarterback Dustin Vaughn is in the mix. And Jones is working his tail off to be the number two guy.
"I expect that and I expect it from the other quarterbacks here," said Fichtner. "They are in a great competition."