A transitive verb meaning to pester, badger, or persistently beg someone for something.
子供が新しいおもちゃをせがんだ。
The child begged for a new toy.
彼は母に毎月仕送りをせがんでいる。
He keeps pestering his mother for financial support every month.
店員に試供品をくれとせがんだ。
He pestered the clerk to give him a sample.