September is Etymology Month (30)

ПОДКУЗЬМИТЬ [podkuz'mit'] 'to do someone a bad turn'. From the festival of Sts. Kuz'ma and Dem'jan (17th October, OS), at which deals were concluded and accounts settled between employer and employee, originally 'to dispel hopes connected with St. Kuz'ma's Day'. Cf. объегорить 'to cheat', originally referring to the practice of reneging on similar deals struck before St. George's Day (Егор(ий) from Георгий, patron saint of agriculture), 26 November NS.