The small bits of fluff from a sock that still cling to your foot after you have taken a sock off. These occur particularly if it has been a sweaty day and the socks are relatively new.
Ugh I took my socks off to go swimming and found some sock nuggets clinging to my feet
A hardo is a person who tries extremely hard at everything. Most times a hardo will try very hard at things that do not require excessive effort. For example, sports practices, gym class, etc.
Wow did you see Jack at practice today? What a hardo!