Immune to refers to resistance to something, either emotionally, mentally or physically. Some synonyms for immune to include impervious, unaffected, unresponsive, insusceptible, invulnerable, resistant and indifferent. Impervious means not allowing something to pass through, while unaffected refers to remaining unchanged despite what happens to one thing. Unresponsive refers to a lack of reaction, while insusceptible means not able to be influenced or affected. Invulnerable means incapable of being hurt, damaged or affected negatively. Lastly, indifferent means lacking interest or concern or being apathetic towards something. These synonyms can help one to articulate their thoughts and emotions accurately and precisely.