It's primarily a skill game, although luck plays a huge role. In any single given hand, luck is the predominant factor in who will win or lose. However, poker players don't play a single hand. They play hand after hand after hand & and overall, skill dominates.
In other words, poker becomes a game of skill after around 1,500 hands. To put this into perspective, most online players are likely to play 1,500 hands in 19 to 25 hours and less than that if they play multiple tables at the same time.