Unshakeable is a term that describes something that is strong and immovable. It can be used to describe a person's beliefs, opinions, or convictions. The crossword solutions for unshakeable are ADAMANT (7 letters), SOLID (5 letters), and FIRM (4 letters). ADAMANT means unyielding or inflexible, SOLID implies strength and stability, and FIRM suggests a strong and unwavering commitment. Together, these words provide an accurate description of the term unshakeable.