milquetoast:
Milquetoast is an insult popularised by H.T. Webster’s character, Caspar Milquetoast, which was a deliberate misspelling of the dish milk toast. It refers to a person who has a meek or timid disposition. [Wikipedia]
From “Why in the world is Saudi Arabia sanctioning Canada?” Daniel Drezner, WaPo:
If this is an example of what Secretary of State Mike Pompeo meant when he said he wanted U.S. diplomats to get their swagger back, then he might be confusing “swagger” with “milquetoast.”
