for the reason that; due to the fact that: The boy was absent because he was ill.
because of, by reason of; due to: Schools were closed because of heavy snowfall.
Origin: 1275–1325;Middle Englishbi causeby cause
Synonyms 1. Because, as, since, for, inasmuch as agree in implying a reason for an occurrence or action. Because introduces a direct reason: I was sleeping because I was tired.As and since are so casual as to imply merely circumstances attendant on the main statement: As (or since ) I was tired, I was sleeping. The reason, proof, or justification introduced by for is like an afterthought or a parenthetical statement: I was sleeping, for I was tired.Inasmuch as implies concession; the main statement is true in view of the circumstances introduced by this conjunction: Inasmuch as I was tired, it seemed best to sleep.