Off side / encroachment / neutral zone infraction

Offside is when the defense does it. Encroachment is when the offense does it. Both are neutral zone infractions.

Offsides means someone (either offense or defense) was on the wrong side of the line of scrimmage when the ball was snapped. If it is the defense, play continues (meaning a free play for the offense).

Neutral zone infraction means that the defense started to soon which caused an offensive player to react. Play is stopped immediately.

The big difference between offsides and neutral zone infraction is whether play is stopped immediately.

Encroachment means that the defensive player actually made contact with the offensive player or has a clear shot at the quarterback. Encroachment also stops play immediately.

A Neutral Zone infraction takes place when a Federation ship/Klingon ship/Romulan ship crosses the respective Federation, Klingon, or Romulan Neutral Zone border even for a short time:

you know you are in trouble when they turn into bees...

Those damn Romulan treaty defying genetic experiments!