The issue : what is the motivation for the nick-name Sneglu-Halli ?
Actually, the guy is called "Sarcastic Halli" in English
translations, he is also known as "inn stríði", which is quite
understandable, or even as "Grautar-Halli", that again follows
from the episode told in the "Sneglu-Halli þáttr", Ch. 4.
The dictionary of Cleasby & Vigfusson explaines the word "snegla"
as "(weaver's) shuttle", with reference to Björn Halldórsson,
that is, to Modern Icelandic.
In (Modern) Norse the same word seems to mean "a meager person"
(and this is in accord with Halli's portrait, Ch.2)
The meaning "shuttle" appears to me absolutely unmotivated
except it might be understood as a "dodger, pushful person".
What is your opinion ?