American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

[From the obsolete greeting hail, fellow! ]

a hail-fellow-well-met slap on the back

genial and familiar, esp in an offensive or ingratiating way: a hail-fellow-well-met slap on the back .

hail-fellow-well-met

Used to describe a person or attitude that is overly, often falsely, friendly.

Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited