Often used in first person
shooter games, "spotlocking" is when a
player sits somewhere and aiming directly at a passage of some sort and therefore "spotlocking" that area.
It could be a doorway or a tunnel for example, and players that runs through the passege are easily shot down.
"Spotlocking" is mostly used by some camper noob who cannot
get enough kills.
"OMG, some n00b is spotlocking the door, I can't
get through"
"
Guys I need some kills, I think I'll spotlock this
corner"