A poker player is said to scoop the pot in a hi-lo variant if they win both the high and low hands, thus winning the entire pot. A player has not scooped if they had to chop the pot with another player, even for only a quarter of the pot. (see Quartering)
In casinos, scoop is also often used to describe a game which offers a variant of a kill for a hi-lo game: if a player scoops the pot on a hand, the next hand is played for double stakes, just like in a kill. Unlike a standard kill, it is not required that the player win two pots in a row: the act of scooping triggers the kill.
Generally, a player has not scooped if there was no low qualifier in a game where the low hand must qualify for low. You must have both a valid low and high, and win both, in order to scoop. Players themselves might still describe the situation as a "scoop", since one player has won the entire pot, but casinos will not generally treat it as a scoop for purposes of triggering the kill. House rules, however, may vary from casino to casino.
In strategy for a hi-lo variant, it is usually best to aim to scoop the pot: playing a hand which can only win half the pot at best is often (though not always) unprofitable.