Almost never appears alone in modern Chinese — used in compounds:
冗长 (rǒngcháng, lengthy),
冗余 (rǒngyú, redundancy, e.g. data redundancy),
冗员 (rǒngyuán, redundant staff),
冗杂 (rǒngzá, miscellaneous). The phrase
拨冗 (bō rǒng, 'to make time despite a busy schedule') is a polite formula in invitations.