Как по Английски будет secondeur

noun

A defensive player positioned just behind the line of scrimmage.

Примеры использования:

He's one of the league's quickest linebackers and can cover tight ends and running backs.

adjective

Denoting or relating to the activity of playing linebacker.

Примеры использования:

The team wanted its defence to be managed by a strong linebacking core

noun

A person who seconds a motion (= official suggestion made at a meeting) so there can be a discussion or vote

Примеры использования:

We need a proposer and seconder for each nomination to the committee.