Man-of-war (?), n; pl. Men-of-war. 1. A government vessel employed for the purposes of war, esp. one of large size; a ship of war. [wns=1]
Syn. -- ship of the line.
[1913 Webster]

2. The Portuguese man-of-war.
Syn. -- , jellyfish.
[WordNet 1.5]

Man-of-war hawk (Zoöl.), the frigate bird. -- Man-of-war's man, a sailor serving in a ship of war. -- Portuguese man-of-war (Zoöl.), any species of the genus Physalia; it is a hydrozoan having both medusa and polyp stages present in a single colony. It floats on the surface of the sea by a buoyant bladderlike structure, from which dangle multiple long tentacles with stinging cells. Its can cause severe rashes when it comes in contact with humans swimming in the area. See Physalia.
[1913 Webster]