1. lacking courage or resolution; cowardly; faint-hearted; timid.
2. proceeding from or indicating a cowardly spirit.
Margaret would not speak to her friends for a week after they did not stand up for her while a false rumor about her was spreading around school. She knew that they would have gotten bad reputations because of the situation as well, but she hadn't realized until now how pusillanimous her "best friends" really were.
a scolding, vicious woman; hag; shrew.
"Ugh, today my aunt was screaming at me about something stupid again," complained Patrick.
"What a harridan!" replied his friend Stewart. "You should give that horrible old bag a piece of your mind one of these days!"
There. And now you have another word to use in place of 'bitch.' (I don't mind that word, but sometimes people just use it when it's totally unnecessary.)