To notice, observe, learn, or understand, especially something otherwise overlooked.
To adopt a practice in which others already engage.
To continue or build upon (for example, a task, analysis, or narrative), beginning from a point at which someone has previously stopped.
To explore; to see; to view; inspect and examine secretly, as a country.
To act as a spy.
To search narrowly; to scrutinize.
To spot; to catch sight of.
A defensive player assigned to cover an offensive backfield player man-to-man when they are expected to engage in a running play, but the offensive player does not run with the ball immediately.
A person who secretly watches and examines the actions of other individuals or organizations and gathers information on them (usually to gain an advantage).