Open English Wordnet
Adjectives
(a)unfriendlynot disposed to friendship or friendliness“an unfriendly coldness of manner”, “an unfriendly action to take”
(s)hostile, uncongenial, unfriendlyvery unfavorable to life or growth“a hostile climate”, “an uncongenial atmosphere”, “an uncongenial soil”, “the unfriendly environment at high altitudes”