Limp
Entering the pot preflop by paying the blind without raising
Definition
Limping means entering a pot preflop by just paying the big blind instead of raising. We distinguish the open-limp (being the first to enter by limping) from the limp-behind or over-limp (limping after one or more limpers). In deep-stacked 6-max cash games, the open-limp is absent from solid strategies: the "raise or fold" rule dominates, because limping surrenders the initiative, offers zero fold equity and builds multiway pots where even good hands lose value. A player who open-limps and then raises (limp-raise) only with monsters becomes instantly readable. But limping isn't always a mistake: in heads-up and in short-stacked Spin & Go play, solvers limp a significant part of the SB range — including strong hands to protect the range and enable a balanced limp-raise. Likewise, completing in the SB in an unopened pot, or over-limping small pairs and suited connectors behind several limpers, can be correct thanks to the price offered. The key distinction: a limp that belongs to a balanced strategy has nothing in common with a limp born of passivity.
In 100bb 6-max cash, UTG limps AA "to trap": playable once, but if they ONLY limp their monsters, their strategy is transparent and exploitable. Conversely, in heads-up at 15bb, the solver limps ~60% of hands from the SB, from the weakest playable holdings up to mixed-in premium hands — a balanced, unexploitable limping range.