buttoned-up
Very conservative, unimaginatively conventional, or old-fashioned, as of a person's clothing, attitude, behavior, or beliefs. He spent his entire adult life as a buttoned-up clerk, so, when he turned 65, he decided it was time for adventure. Wait, I'm sorry, are you saying that buttoned-up Aunt Ida was a groupie for Grand Funk Railroad in the '70s? That's, like, inconceivable! Roger's always lived a buttoned-up life, even when he was in his 20s.
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