Top Definition
When something is so cool and amazing (awesome) that you can't express it without lisping.

Must be spelt with more than one "M", although 3 is more excepted.

Pronounced: Awww-thumb or Awww-fumm
Dude, I can't believe how cool that night was, it was totally Awthummm!
by cg1991 May 20, 2008
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