Uncomfortable, a.
1. Feeling discomfort; uneasy; as, to be uncomfortable on account of one's position.
2. Causing discomfort; disagreeable; unpleasant; as, an uncomfortable seat or situation. The most dead, uncomfortable time of the year. Addison. -- Un*com"fort*a*ble*ness, n. -- Un*com"fort*a*bly, adv.
Shades of meaning
Fernald lists uncomfortable only as an antonym, under comfortable.
He lists it without comment; the entries above explain its neighbors.
Synonyms
none given