τὸ δανείζεσθαι τῆς ἐσχάτης ἀφροσύνης καὶ μαλακίας ἐστίν → being in debt is a mark of extreme folly and moral weakness (Plutarch, On Avoiding Debt 829F3)
σύνηβος, συνηλικιώτης, συνῆλιξ, συνᾶλιξ, ξυνῆλιξ, συνομῆλιξ, ὁμήλικος