Just a pre-requisite of having no luck?

If so, then games such as these are - by definition -strategic: https://www.warlight.net/MultiPlayer?GameID=9607598

I find this rather hard to believe. Therefore, I wonder - are there more specific guidelines other than the ones mentioned above? If so, what? Assuming a game has these constraints of (supposedly) no luck, when does it no longer become a game of skill?

Yes it actually means a game which has no luck involved, so if you use cyclic order (instead of no-luck cycle), it is no longer a "pure skill" game.

A euphemism used in conjunction with another euphemism ("no luck") to enable gambling on a game that still has luck and whose new "no luck" setings actually involve less skill and are not the purest settings possible (no fog + each move order as a single turn would be pure Risk settings).

Edited 10/9/2015 07:16:59

Is the 3x3 map (tic tac toe template) on the forbidden map for pure skill list? Where can i check that?

https://www.warlight.net/Map/1766-TicTacToe

You can see there isn't anything that says the map cannot be used for "Pure Skill" settings.

Maps such as these (https://www.warlight.net/Map/14781-40-Player-Lottery) have

Games on this map are never considered pure-skill.

Tic-tac-toe doesn't, so "Pure Skill" settings can be applied on the map.