1.
-noun
An online, techno-themed, third-person shooter with three different modes: deathmatch, touchdown (basically capture the flag), and chaser (all versus one). Games can have up to 12 players (6 vs 6) with each player having up to 3 weapons and a skill. "S4" stands "Stylish eSper Shooting Sports".

2.
-intransitive verb
-S4,-S4'ed,S4'ing
to play S4 League

Stylish eSper Shooting Sports, with 3D sci-fi shooter with a third-person view and a techno beat. Play Death Match or Touch Down (capture the flag) modes and earn money to buy armor or more weapons. A very addictive game, and its something to definetly look at.