If you star crossed out of a showdown is it considered a combat?

No, playing Star-Crossed does not determine whether a situation is a "combat"—the existence of combat is determined by the units present at the battlefield, not by the spells played.

Here is the breakdown of how this works:

1. What determines Combat?

According to Rule 454 and Rule 456, a combat exists at a battlefield if units controlled by opposing players are present there.

• If you play Star-Crossed during a showdown, it simply removes units from the board.
• If removing those units leaves only one player's units (or no units) at the battlefield, the battlefield may stop being "contested," but it does not retroactively change the fact that a combat was staged there, nor does the act of playing Star-Crossed itself change the nature of the showdown.

2. Does Star-Crossed end a Showdown?

No. According to RiftJudge FAQ #7670, a showdown does not end just because units are moved off the battlefield. The showdown continues until all players pass focus in a row.

3. The Sequence

If you play Star-Crossed during a showdown:

1. Chain: Star-Crossed is added to the chain.
2. Resolution: Star-Crossed resolves, returning the target units to hand.
3. State: The showdown remains ongoing (Rule 348).
4. Combat Status:
   • If, after the units are returned to hand, there are still units from both players at the battlefield, it remains a Combat Showdown.
   • If the units returned by Star-Crossed were the only units representing one or both sides of the combat, the combat is no longer "staged" with opposing units. However, because a showdown only ends when players pass focus, the players continue to have the opportunity to play spells until they both pass.

In summary: Playing Star-Crossed is a reaction that affects the board state during a showdown, but it does not "create" or "cancel" a combat definition—it only alters the presence of the units that are currently defining that status.