'Woodwose' is a modernised spelling of Old English wudewása, a word that seems to have originally meant something like 'woodland outcast', simply referring to people forced to live wild in the forest. Over time, the word took on a more supernatural element, so that it came to mean something more like a 'forest spirit'. In this later sense the word wása came to mean something like 'troll' or 'faun', and in heraldry a woodwose would appear as a wild hairy man, often clad in leaves and bearing a club.

It seems that Saeros' insult to Túrin was based on the original meaning of simply a wild man of the woods (and indeed Túrin would later call himself 'Wildman of the Woods'). The shortened form 'Woses' was later used by Tolkien as a word among the Rohirrim for the wild people known as Drúedain (and also called 'Wild Men of the Woods') who lived in the forests of the White Mountains. There does not seem to be a direct connection between the two uses (indeed, they represent translations of different words: an unknown Elvish insult from Saeros, and the word rógin in the language of the Rohirrim).

When Saeros called Túrin a 'woodwose' in Menegroth, he meant this as simple insult (Túrin had a tangled and unkempt appearance, having just come from the forest, hence Saeros' use of a name meaning 'wild man of the woods'). It doesn't have a direct connection with the people known in Rohan as Woses, though the two uses do indeed share a common etymological origin (see note 1 above).