godfather

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A man who sponsors a person at baptism.
• noun One that has a relationship to another person or to something that is the equivalent of being a baptismal sponsor.
• noun Slang The leader of an organized crime family.
• transitive verb To serve as or as if a godfather to.

from The Century Dictionary.

• To act as godfather to; be sponsor for.
• noun In the liturgical churches, a man who at the baptism of a child makes a profession of the Christian faith in its name, and guarantees its religious education; a male sponsor. See sponsor.
• noun A juryman, as jocularly held to be godfather to the prisoner.

from the GNU version of the Collaborative International Dictionary of English.

• noun A man who becomes sponsor for a child at baptism, and makes himself a surety for its Christian training and instruction. Correlative of godmother.
• transitive verb rare To act as godfather to; to take under one's fostering care.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A man present at the christening of a baby who promises to help raise the child in a Christian manner; a male godparent who sponsors the baptism of a child.
• noun A small post which is used in repairing a fence. For instance attached to and supporting an existing broken fence post.
• noun A mafia leader.
• verb transitive To act as godfather to.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun someone having a relation analogous to that of a male sponsor to his godchild
• noun any man who serves as a sponsor for a child at baptism