“原形毕露”常见的英文表达有 “show one's true colors/nature” 或 “reveal one's true self”，也可用 “be unmasked” 来表示“暴露本来面目；原形被揭穿” 。以下为具体例句：
show one's true colors/nature：
Once put under pressure, he soon showed his true colors. 一受到压力，他很快就原形毕露了。
The fraud finally showed his true nature when confronted with the evidence. 面对证据，这个骗子终于原形毕露了。
reveal one's true self：
In difficult situations, people often reveal their true selves. 在困难的情况下，人们往往会原形毕露。
be unmasked：
The criminal's true identity was unmasked at last. 这个罪犯的真面目最终被揭穿了（原形毕露）。