The keyword phrase "11 sep rocky rabbit enigma" functions as a compound noun phrase. The principal part of speech, which constitutes the main point or head of the phrase, is the noun "enigma". This identifies the core subject as a puzzle, mystery, or a situation that is difficult to understand.
The other words in the phrase act as adjectival modifiers that specify and narrow the focus of the central noun, "enigma." "11 sep" is a noun adjunct providing a specific temporal or contextual marker (September 11th). "Rocky" is a descriptive adjective, suggesting the enigma is difficult, unstable, or fraught with obstacles. "Rabbit" is another noun adjunct that defines the subject matter of the puzzle, indicating it pertains to something literally or figuratively referred to as a "rabbit."
Therefore, the grammatical structure dictates that the primary focus of an article using this keyword must be the analysis or exploration of a mystery. The terms "11 sep," "rocky," and "rabbit" are not the main subjects but are crucial descriptors that define the specific context, nature, and content of this central enigma. The article's main point would be to unravel this particular puzzle.