sobrecoger
From LSJ
πρὶν τοὺς ἰχθῦς ἑλεῖν σὺ τὴν ἅλμην κυκᾷς → you're mixing the sauce before catching the fish | don't count your chickens before they are hatched | don't count your chickens before they hatch | first catch your hare | first catch your rabbit | first catch your rabbit and then make your stew | first catch your hare, then cook it | first catch your hare, then cook him
