kept one nose to grindstone (verb) keep one's nose to the grindstone: work doggedly
Sinonime: associated, bilateral, collective, communal, conjoint, conjunct, connected, convertible, correlative, dependent, give-and-take, given and taken, interactive, interchangeable, interchanged, interdependent, intermutual, joint*, partaken, participated, public, reciprocal, reciprocated, related, requited, respective, returned, two-sided, united