Definition of swifter:
(n) :
(nautical) A rope used to retain the bars of the capstan in their sockets while it is being turned.
(n) :
(nautical) A rope used to encircle a boat longitudinally, to strengthen and defend her sides.
(n) :
(nautical) The forward shroud of a lower mast.
(v) :
(nautical, transitive) To tighten (e.g. slack standing rigging) by bringing the opposite shrouds nearer.