The Collaborative International Dictionary of English v.0.48:
Freshen \Fresh"en\, v. t. [imp. & p. p. Freshened; p. pr. &
vb. n. Freshening]
1. To make fresh; to separate, as water, from saline
ingredients; to make less salty; as, to freshen water,
fish, or flesh.
2. To refresh; to revive. [Obs.] --Spenser.
3. (Naut.) To relieve, as a rope, by change of place where
friction wears it; or to renew, as the material used to
prevent chafing; as, to freshen a hawse. -- Totten.
To freshen ballast (Naut.), to shift Or restore it.
To freshen the hawse, to pay out a little more cable, so as
to bring the chafe on another part.
To freshen the way, to increase the speed of a vessel.
--Ham. Nav. Encyc.