What it means
آب زیرکاه (âb zir-e kâh) is a compound noun describing a person who appears quiet, gentle, or unassuming while secretly pursuing their own agenda. All three components, آب (water), زیر (under), and کاه (straw), are native Persian words. The image comes from irrigation channels in traditional Persian farming: water flowing silently beneath a layer of dry straw, invisible and underestimated, but capable of eroding everything in its path. A close equivalent in meaning is دورو (doru), “two-faced,” though آب زیرکاه implies a more patient, calculated deception rather than simple dishonesty.
How to use it
- بهش اعتماد نکن، آب زیرکاهه. (behesh e’temâd nakon, âb zir-e kâh-e.) “Don’t trust him, he’s a sly one.”
- از اون آب زیرکاهها بود که آدم متوجه نمیشه. (az oon âb zir-e kâh-â bud ke âdam motavajjeh nemi-she.) “She was the kind of sly person you never see coming.”
- همه فکر میکردن ساکته، ولی آب زیرکاه بود. (hame fekr mi-kardan sâket-e, vali âb zir-e kâh bud.) “Everyone thought he was quiet, but he was scheming underneath.”
- یه آب زیرکاه توی اون جمع بود که همه چیزو خراب کرد. (ye âb zir-e kâh tu-ye oon jam’ bud ke hame chizo kharâb kard.) “There was a schemer in that group who ruined everything.”
Cultural note
The idiom reflects a deep cultural awareness in Iranian society of the gap between outward appearance and inner motive. Persian literature and proverbs frequently warn against trusting surfaces: still water is more dangerous than rushing water, and silence can mask cunning. Calling someone آب زیرکاه is a serious accusation in Persian social contexts, implying calculated, long-term deception rather than a moment of dishonesty.