Both of these verbs can refer to either pleasant or unpleasant smells; see web address 1 and 2 for their LSJ entries.
The headword ὠδώδει is the pluperfect -- functioning as an imperfect -- of ὄζω (omicron 73), which like English "to smell" can be transitive or intransitive. The gloss ἔπνει is the imperfect of πνέω ; this use of the imperfect suggests that the scent continues to waft up from the smelly object, since the basic meaning of πνέω is "blow."
The headword is almost certainly taken from Athenaeus, Deipnosophists 2.39C (= Greek Anthology 13.29), the epigram about the bibulous Athenian comic poet Cratinus (kappa 2344), who 'used to reek of every cask'.