Both of these verbs can refer to either pleasant or unpleasant smells; see web address 1 and web address 2 for their LSJ entries.
The headword w)dw/dei is the pluperfect -- functioning as an imperfect -- of o)/zw (omicron 73), which like English "to smell" can be transitive or intransitive. The gloss e)/pnei is the imperfect of pne/w; this use of the imperfect suggests that the scent continues to waft up from the smelly object, since the basic meaning of pne/w is "blow."
The headword is almost certainly taken from Athenaeus, Deipnosophists 2.39C [2.9 Kaibel] (= Greek Anthology 13.29), the epigram about the bibulous Athenian comic poet Cratinus (kappa 2344), who 'used to reek of every cask'.