I thought real hard, trying to will the word into my awareness. When that didn't work, I continued to think real hard. Sometimes I furrowed my brow. No dice.
Here's what happened when I enlisted Ron the Drummer's help during rehearsal.
Me: "Hey, Ron. What's a word that means 'brief,' with two syllables, accent on the first syllable?"
Ron: [thinks for a moment] "Brief ... two syllables ..."
Me: "Yeah, you know. Like 'fleeting.'"
My brain is weird.