Loggerheads

noun

1. A stupid person; a blockhead, a dolt.
2. A metal tool consisting of a long rod with a bulbous end that is made hot in a fire, then plunged into some material (such as pitch or a liquid) to melt or heat it.
3. A post on a whaling boat used to secure the harpoon rope.
4. (often in the plural) A thistle-like flowering plant of the genus Centaurea, particularly the common knapweed (Centaurea nigra).
5. Used as the name of various animals with large heads.