σκυθρωπάζειν
From LSJ
Φιλοκαλοῦμέν τε γὰρ μετ' εὐτελείας καὶ φιλοσοφοῦμεν ἄνευ μαλακίας → Our love of what is beautiful does not lead to extravagance; our love of the things of the mind does not makes us soft.
Greek > English (Woodhouse Verbs Reversed)
(see also σκυθρωπάζω): look angry, look gloomy, look sullen