"Sticking like barnacle" indicates clinginess or persistence. Its antonyms could be described as detachment, agility and mobility. Antonyms for "sticking" may include loosening, disentangling, or slipping away. Alternatively, antonyms for "barnacle" could include mobility, flexibility, or freedom. Instead of sticking stubbornly like a barnacle, words such as agile, light, and nimble could be applied to indicate a sense of lightness and ease. The opposite of sticking like a barnacle is to be able to move, shift and transform, highly important qualities in today's rapidly changing world.