A far standing attack is an attack performed at (somewhat) far range in a state where you are standing (cf. standing attack and normal move).
In 2D fighting games, this is an idea that lies on the flip side of the close standing attack.
Generally, compared to their “close” counterparts, the reach will be longer, and the attack hitbox will have better priority, making them better attuned to zoning; depending on what the move is, it may also be better at checking those jumping in.
Many far standing attacks don’t take cancels, so they often cannot be used in combos.