一举 (yī jǔ) means 'in one go' (adverb) or 'a single decisive action' (noun). As an adverb, it emphasizes achieving a result in one stroke, unlike 一口气 (yī kǒu qì, 'without stopping') which focuses on continuity, and 一并 (yí bìng, 'together') which implies including everything. As a noun, it refers to a specific move (often crucial), while 行动 (xíng dòng) is a general action or operation.