Lewis Short
(adjective) : ex-pugnābĭlis, e, expugno
* That may be taken, carried, or reduced by assault; expugnable (very rare): urbs terra marique expugnabilis est,Liv. 33, 17, 8: ne magnis quidem exercitibus,Tac. H. 3, 78: situ non expugnabile robur,Stat. Th. 6, 103: fluvius,i. e. exhaustible,id. ib. 4, 836.
Charlton T. Lewis, Charles Short, A Latin Dictionary