WordNet sense 1 (a crystal of snow):

snowflake

WordNet sense 2 (a person with an unusual or odd personality):

eccentric, geek, oddball, eccentric person

WordNet sense 3 (a small fragment of something broken off from the whole):

bit, chip, fleck, scrap

WordNet sense 4 (come off in flakes or thin small pieces):

peel, peel off, flake off