I happen to be studying lojban at the moment, and I think the designers have defined linguistic ambiguity not as the opposite of specificity (one of the first lojban words I learned was "zo'e" /ZO.he/, which means something like "contains contextually sensitive information that makes this utterance true, the exact value of which is irrelevant or obvious"), but rather as a linguistic property whereby a semantic construct cannot be pinned down to communicating a specific value. The classic English language example is "time flies like a banana", in which any of the first three words can be the verb.