also: ごんか
noun
promptly; immediately; without hesitation
Used almost exclusively in the set phrase 言下に (げんかに), meaning 'without a moment's delay' or 'right away' in response to something said. Rarely used outside this adverbial phrase.
彼は言下にその申し出を断った。
He promptly refused the offer.
質問されると、彼女は言下に答えた。
When asked, she answered immediately.
Compound of 言 (word, speech) and 下 (under, below), literally 'under the word', suggesting an immediate reaction following someone's words. The exact historical derivation is uncertain.