A word originating from a comic strip character in the 1920's named Casper Milquetoast. The word has come to define someone unassertive and timid.
The first time I ever heard this word was in an episode of The Gilmore Girls.
". . . You can't be a milquetoast muppet. You have to have pointy teeth and jaws that snap. The meek shall not inherit the earth!"
I saw this word printed in a newspaper article describing the psyche of a hockey coach. His team had just lost an NHL series. The word was used to define the following: soft, dispassionate, non-aggressive, unbold, unwillful, non-determination and lacking strength of character.
"The coach's milquetoast attitude towards the opposition and sticking to his dogged offensive attitudes had been their unravelling."