[jack of all trades] {n.}, {informal} (Often followed by the words "master of none.") A person who is knowledgeable in many areas. Can be used as praise, or as a derogatory remark depending on the context and the intonation.
* /Peter is a jack of all trades; he can survive anywhere!/* /"How come Joe did such a sloppy job?" Mary asked. "He's a jack of all trades," Sally answered./