Synonyms for Unfriendly (same or very similar meaning)
WordNet sense 1 (not friendly):
inimical
WordNet sense 2 (characterized by enmity or ill will):
hostile
WordNet sense 3 (very unfavorable to life or growth):
uncongenial
WordNet sense 4 (unfavorable to life or growth):
inhospitable
WordNet sense 5 (lacking warmth of feeling):
chilly
From the ODE community, based on WordNet
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