μονοῦσθαι
From LSJ
Ἀμήχανον δὲ παντὸς ἀνδρὸς ἐκμαθεῖν ψυχήν τε καὶ φρόνημα καὶ γνώμην πρὶν ἂν ἀρχαῖς τε καὶ νόμοισιν ἐντριβὴς φανῇ → It is impossible to know the spirit, thought, and mind of any man before he be versed in sovereignty and the laws
Greek > English (Woodhouse Verbs Reversed)
(see also: μονόω) be isolated
Lexicon Thucydideum
seiungi a ceteris, to be separated from the rest, 2.81.5, 3.105.4, 4.126.1, 5.8.4, 5.40.1, 5.58.2, 6.101.6.