to nourish a viper in one's bosom

9.9

Help or trust someone who later harms you

idiom

Literature

: acoger a una víbora en el seno

The board felt they had nourished a viper in their bosom by promoting him to manager.

Examples

She later regretted that she had nourished a viper in her bosom, as he betrayed her trust.
Trusting Mark turned out to be like nourishing a viper in one's bosom; he eventually undermined the whole project.
Don't nourish a viper in your bosom!
He realized he had nourished a viper in his bosom for too long.
She realized too late that she had nourished a viper in her bosom when he sabotaged her efforts.
After his betrayal, the team understood that they had nourished a viper in their bosom by trusting him.
He learned that nourishing a viper in one's bosom could lead to unexpected consequences when his ally turned against him.

Surface Forms

nourish a viper in one's bosom infinitive

nourished a viper in one's bosom past

nourished a viper in one's bosom past participle

nourishing a viper in one's bosom present participle

nourishes a viper in one's bosom third person singular

Morphology

nourish + a + viper + in + one + bosom

The literal parts — 'nourish' (to feed/support), 'viper' (a dangerous snake) and 'in one's bosom' (kept close/trusted) — create a clear concrete image of feeding a dangerous creature close to oneself, so a B1 learner who knows the words can plausibly infer it refers to supporting or keeping someone dangerous. However, the meaning is a metaphorical/idiomatic extension (trusting or fostering a treacherous person) and the exact nuance is not fully predictable without prior exposure.

Etymology

Nourish a viper in one's bosom comes from the vivid image of feeding a viper, a dangerous snake, close to your bosom or heart, so the snake grows strong while it sits near you. So it means to support or trust someone who later 'betrays' or harms you.