James Champlin Fernald,
English Synonyms and Antonyms
“ An impediment may be either what one finds in his way or what he carries with him; impedimenta was the Latin name for the baggage of a soldier or of an army. The tendency is to view an impediment as something constant or, at least for a time, continuous; as, an impediment in one's speech. A difficulty or a hindrance may be either within one or without; a speaker may find difficulty in expressing himself, or difficulty in holding the attention of restless children. An encumbrance is always what one carries with him; an obstacle or an obstruction is always without. ”
