serious
From LSJ
English > Greek (Woodhouse)
adjective
earnest: P. and V. σπουδαῖος (Sophocles, Fragment), ἔντονος, σύντονος; see also eager.
be serious, v.: P. and V. σπουδάζειν.
look serious: V. σεμνὸν βλέπειν.
difficult to deal with: P. and V. ἄπορος, ἀμήχανος (rare P.). Ar. and P. χαλεπός.