Delineation, as a word, means to describe or depict something in detail. On the other hand, antonyms of delineation would be words that refer to unclear or vague forms of expression. Some appropriate antonyms for delineate might include obfuscate, obscure, or blur. Obfuscation involves intentionally making something confusing or unclear, while obscuring refers generally to making something difficult to see or understand. Similarly, blurring could mean intentionally distorting something, making it harder to understand or see. All three of these words are in direct contrast to what it means to delineate, which is to describe something with clarity and precision.