The hobnailed jackboot has a different design and function than the first type. It is a combat boot that is designed for marching. It rises to mid-calf or higher with no laces and usually has a leather sole with hobnails.
The word is commonly used in Britain as a synonym for fascism. The Russian expression "под сапогом" "under one's boot" translates as "under one's heel" and symbolizes oppression. The Spanish expression "tener (algo o alguien) bajo la bota" or "to have (something or somebody) under the boot" has the same meaning.