litigant
From LSJ
μηδέν' ὀλβίζειν, πρὶν ἂν τέρμα τοῦ βίου περάσῃ μηδὲν ἀλγεινὸν παθών → Count no man blessed 'til he's passed the endpoint of his life without grievous suffering. (Sophocles, King Oedipus 1529f.)
subs.
P. ἀντίδικος, ὁ or ἡ. Be a litigant, v.: Ar. and P. ἀντιδικεῖν.