fly by the seat of one's pants

From LSJ

κινδυνεύει μὲν γὰρ ἡμῶν οὐδέτερος οὐδὲν καλὸν κἀγαθὸν εἰδέναι, ἀλλ᾽ οὗτος μὲν οἴεταί τι εἰδέναι οὐκ εἰδώς, ἐγὼ δέ, ὥσπερ οὖν οὐκ οἶδα, οὐδὲ οἴομαι· ἔοικα γοῦν τούτου γε σμικρῷ τινι αὐτῷ τούτῳ σοφώτερος εἶναι, ὅτι ἃ μὴ οἶδα οὐδὲ οἴομαι εἰδέναι. → for neither of us appears to know anything great and good; but he fancies he knows something, although he knows nothing; whereas I, as I do not know anything, so I do not fancy I do. In this trifling particular, then, I appear to be wiser than he, because I do not fancy I know what I do not know.

Source

Translations

improvise

Arabic: ⁧إرتجل⁩; Asturian: improvisar; Belarusian: імправізаваць or; Bulgarian: импровизирам; Catalan: improvisar; Chinese Mandarin: 即興/即兴, 现抓; Czech: improvizovat; Danish: improvisere; Dutch: improviseren; English: fly by the seat of one's pants, improvise, improvize, play by ear, punt, think on one's feet, wing it; Finnish: improvisoida, sepittää; French: improviser; German: improvisieren; Greek: αυτοσχεδιάζω; Ancient Greek: ἀποσχεδιάζω, αὐτοσχεδιάζειν, αὐτοσχεδιάζω, ἐπισχεδιάζω, εὐθυρρημονέω, παραχρῆμα λέγειν, σχεδιάζω; Hungarian: improvizál, rögtönöz; Icelandic: leika af fingrum fram, snarstefja, spinna; Irish: seiftigh; Italian: improvvisare, parlare a braccio; Maori: tito ohia; Norwegian: improvisere; Polish: improwizować, zaimprowizować; Portuguese: improvisar; Romanian: improviza; Russian: импровизировать, сымпровизировать; Spanish: improvisar; Swedish: improvisera; Ukrainian: імпровізувати or; Vietnamese: ứng biến, ứng tác, ứng tấu