ACTUAL, something real and effective; or that exists truly and absolutely. See REAL, EXISTENCE, etc.

In Philosophy, we say, actual Heat, or Cold; in opposition to Virtual or Potential. See POTENTIAL, etc.

Actual Heat, considered actively, is the act of producing Heat. Passively taken, it is the quality whereby a body is denominated Hot. — Virtual or Potential Heat, actively taken, is the power or faculty of producing Heat; passively taken, it should be the power or faculty of being heated, or of receiving actual Heat. See HEAT, COLD, etc.

In Theology, we say, actual Grace, in opposition to Habitual Grace. See HABITUAL.

Actual Grace is that which God gives us, to make or enable us to act, to do some action. — Habitual Grace is sanctifying Grace, a habit of Charity, or a habit inherent in the soul, which renders us agreeable to God, and objects of eternal recompense. See GRACE.

So, Actual Sin is used in opposition to Original Sin. See SIN.

Actual Sin is that committed knowingly, by a person arrived at years of discretion. Original Sin is that we contract by descent, as being children of Adam. See ORIGINAL.