As nouns the difference between compression and biker
is that compression is an increase in density; the act of compressing, or the state of being compressed; compaction while biker is a person who rides a bicycle.
As nouns the difference between pedestrian and biker
is that pedestrian is somebody walking rather than using a vehicle; somebody traveling on foot on or near a roadway while biker is a person who rides a bicycle.
As an adjective pedestrian
is (not comparable) of or intended for those who are walking.