To respond in advance
An anticipatory response to expected changes in the environment of a system
To appropriate first.
To prevent or beat to the punch, to forestall an expected occurrence by acting first.
To displace or take the place of (by having higher precedence, etc).
To secure (land, etc.) by the right of preemption (purchasing before others, e.g. land because one already occupies it).
To make a preemptive bid at bridge.
A preemptive bid.