اللي على راسه بطحة بيحسس عليها (illi ʿala rasu baṭḥa byiḥassis ʿalayha)

Literally: He who has a bump on his head keeps touching it

Example: “لم يتهمه أحد، لكنه بدأ يدافع عن نفسه؛ اللي على راسه بطحة بيحسس عليها.” — Nobody accused him, but he started defending himself; a guilty conscience needs no accuser.

Origin: An Egyptian proverb: someone with a bump on the head keeps touching it, and so draws attention to it. A guilty person, in the same way, gives himself away by reacting to any hint. Baṭḥa is a bump or bruise. No first use is documented.