What is an antonym for friendly?

Here are some antonyms for "friendly", depending on the context:

General:

* Unfriendly

* Hostile

* Cold

* Aloof

* Unwelcoming

* Unkind

* Rude

* Aggressive

More specific:

* Antagonistic (showing active opposition)

* Averse (having a strong dislike)

* Bitter (having a strong feeling of resentment)

* Confrontational (likely to cause arguments)

* Distant (not close or familiar)

* Formal (not casual or informal)

* Reserved (slow to reveal emotions)

The best antonym will depend on the specific situation.