Capably comes from capable + -ly. Capable is from Late Latin capābilis ('able to hold'), from Latin capere ('to take'). The historical trail runs through capābilis in Latin and capere in Latin. Morphologically, capably is transparent: it draws on capable + -ly. Used as an adverb, capably now means "in a competent and effective manner", so the present definition can be read against the older forms and meanings. The same lexical family is also visible in related forms such as capable, capableness, and capability. The result is a borrowed or transmitted form whose modern spelling carries a compact record of its route into English.