Translation

同盟国 / 味方 / 協力者

Meaning

Ally is a person, group, or country that supports and cooperates with another, especially for a shared goal or against a common opponent. Do not confuse it with allay, which means to reduce fear, worry, or pain.

Examples

• その国は長年にわたる重要な同盟国です。
  The country is a longtime ally.
• 彼女は社内改革の心強い味方になりました。
  She became a strong ally in the workplace reforms.