: To complete a form or questionnaire with requested information.(verb)
: To have one's physique expand with maturity or with surplus weight.(verb)
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Use "fill out" in a sentence
"Through an interpreter, Mansiya told the judge that he needed more time to find an English speaker who could help him fill out an application for asylum."
"I rushed to the LifeLink office on my lunch hour to fill out a mound of paperwork and begin the battery of tests required to become a living donor."
"In the seminars that I present to the public, I often include a printed twenty-part quiz that I ask the audience to fill out to the best of their abilities early on in the presentation."