remuneration;  recompense;  reward;  toll
 exchange;  reciprocation;  give-and-take;  reply;  riposte
 fee contingent upon success;  contingency fee;  completion bonus
 unpaid;  without pay;  gratuitous;  voluntary
 to reward;  to recompense;  to repay;  to retaliate;  to get revenge
 to reward;  to recompense;  to repay;  to retaliate;  to get revenge
 payment (system) for medical services
 officer's compensation or remuneration
 to reward;  to recompense;  to repay;  to retaliate;  to get revenge
 reward;  recompense;  return;  punishment;  retribution
 debt bondage (ritsuryo system);  forced labor on failure to pay a debt
 to be repaid;  to be rewarded