Why is it called 'The Ambiguous Hour'?

am⋅big⋅u⋅ous

  /æmˈbɪgyuəs/ [am-big-yoo-uhs]

–adjective
1. open to or having several possible meanings or interpretations; equivocal: an ambiguous answer.
2. Linguistics. (of an expression) exhibiting constructional homonymity; having two or more structural descriptions, as the sequence Flying planes can be dangerous.
3. of doubtful or uncertain nature; difficult to comprehend, distinguish, or classify: a rock of ambiguous character.
4. lacking clearness or definiteness; obscure; indistinct: an ambiguous shape; an ambiguous future.
Origin:
1520–30; < L ambiguus, equiv. to ambig(ere) be uncertain (amb- ambi- + -igere comb. form of agere to drive, lead, act) + -uus deverbal adj. suffix; see -ous

Related forms:
am⋅big⋅u⋅ous⋅ly, adverb
am⋅big⋅u⋅ous⋅ness, noun

Synonyms:
1. ambiguous, equivocal, cryptic, enigmatic describe conditions or statements not clear in meaning. ambiguous can refer to a statement, act, or attitude that is capable of two or more often contradictory interpretations, usually accidentally or unintentionally so: an ambiguous passage in the preamble. equivocal, usually applied to spoken as well as written language, also means susceptible of two or more interpretations, and it usually suggests a deliberate intent to mislead by avoiding clarity: saving face with an equivocal response to an embarrassing question. cryptic usually refers to intentional obscurity, especially in language, and often implies a private or hidden meaning but stresses resultant mystification or puzzlement: a cryptic remark that left us struggling to interpret his intention. enigmatic focuses on perplexity resulting from a mysterious or imponderable event or utterance, often one of great importance or deep significance: prophetic texts so enigmatic that their meaning has been disputed for centuries. 3. dubious, vague, indeterminate, unclassifiable, anomalous. 4. puzzling, enigmatic, problematic.

Antonyms:
1. explicit. 3. certain. 4. clear, precise, unambiguous.