Wiktionary
n. (context video games English) A video game targeting casual, irregular gamers, typically having few rules to learn and a low initial level of difficulty.
Wikipedia
A casual game is a video game targeted at or used by a mass audience of casual gamers. Casual games can have any type of gameplay, and fit in any genre. They are typically distinguished by their simple rules and lack of commitment required in contrast to more complex hardcore games. They require no long-term time commitment or special skills to play, and there are comparatively low production and distribution costs for the producer.
Casual games are typically played on a personal computer online in web browsers, although they now are starting to become popular on game consoles and mobile phones as well. Casual gamers are typically older than traditional computer gamers, and more often female, with over 74% of casual gamers being female.
Usage examples of "casual game".
Come to that, traders in an anchorage without any of the usual amusements would probably be only too eager for a casual game of runes.
They settled to a casual game of speculation, Harcourt having joined them now that they had parted from the naval officers.