My Gaelic is very sparse but I'll give it a try. The color red is simply dearg. (the 'g' is pronounced as 'k')

The three words I know for socks could be
stocainnean: (f); these are more like tights than socks.
mogan: (m); These are footless socks
osan: (m); stockings or hose

So my best guess would be:
osan dearg (stockings red)