Fed the kitty is an idiom that generally refers to contributing or adding something to a fund or collection. There are several synonyms that can be used for this phrase, such as "donated," "contributed," "pitched in," "put in," and "chipped in." These words can be used interchangeably with "fed the kitty" depending on their context and intended meaning. For example, one may say "I donated to the charity" or "I chipped in for the office party." Whatever the synonym used, it expresses the act of contributing to a common cause or goal.