Unction

A word similar in meaning to 'anointing,' i.e., the practice of smearing with oil, usually on the forehead, in baptism, ordination, coronation, or during prayers for the sick and dying. It is derived from the Latin unctum, 'fat.'

Expreme unction is the Roman Catholic practice of anointing a dying person with sacred oil as a sacrament, i.e., a means of grace by which the person may received the blessings of God in his last hours. The term was coined by Peter Lombard in the 11th Cent.

While the act in itself may be innocuous, even pastorally reassuring for someone who trusts in the Lord Jesus, it is its acclamation as a sacrament (and the possible misunderstanding such an acclamation involves) that has put off reformed and evangelical Christians from embracing it. Scriptures provide not grounds for such an acclamation (as evident even in the article recommended below).

Resouces

R. Foster, "Questions and Answers: 3. Extreme Unction in the New Testament," Scripture 2.1 (Jan. 1947): 25-26. (Scripture is published by the Catholic Biblical Association, UK.)