The antonyms for the word "most unshielded" can be words like "protected," "guarded," "sheltered," "defended," "secure," and "safe." These are the words that denote safety and security, indicating that something has a protective shield or covering that guards against harm or danger. When something is unshielded, it is exposed and vulnerable to any threats that come its way. The opposite of this is being shielded, which gives protection and safety from anything that may cause harm. Whether it is a physical or emotional attack, shielding oneself is always essential for safety and security.