The word "OBSCURE" means not clearly expressed or easily understood, often hard to perceive or ambiguous. Therefore, to find the most similar word in meaning, let's analyze each option:
Clear - This is the opposite of obscure, as it means easily understood or obvious.
Vague - This means not clearly expressed or lacking definite shape, making it similar in meaning to "obscure."
Bright - This relates to light or color intensity and does not align with the meaning of "obscure."
Obvious - This means easily perceived or understood, which opposes "obscure."
Thus, the word most similar in meaning to "OBSCURE" is Vague.