Luck. Although starting with the “A”, “R” and “S”, and knowing no “I” or “E” were huge helps.
I decided to try the straight single vowel “A” instead of trying an “AU” or “OU” pairing, then looked for a letter to compliment an opening “S”. “STAR_” and “SCAR_” both offer a lot as a second guess.
I’m a little surprised I didn’t try Stary or Scary, tbh. “Scram” was the first word that popped into my head, but I wasn’t sure if that would be on “The List”, so I substituted out the “M” for the “F” and slid the “A” to the middle.