Takis is a male Greek name which is rather common in Greece, or at least used to be until recently. Nowadays, Greek people tend to keep their main name and avoid using diminutives or nicknames, as it used to happen in the past.
Takis is one of the most common nicknames, deriving though from several main Greek male names. If you meet a Greek man named Takis, you should ask him what his main name is, to avoid confusion.
Sound of name Takis: Tá-kees
Female Version of name Takis: N/A
Nameday of Takis: If it comes from Panagiotis, then the nameday of Takis is on August 15.
Origin of name Takis
As mentioned earlier, Takis is a nickname. It might derive from name Panagiotis (which is the most common scenario), or from the names Antonios, Eleftherios, Dimitrios. Most chances are that a man named Takis, was originally baptised Panagiotis, but you cannot really be sure unless you ask him.
You can read all pertinent information about these male names at the relevant posts. You can also find the origins and history of each name, as well as information on alternative nicknames for each one of these names.