आकाषात् पतितं तोयं यथा गच्छति सागरम् | सर्व देव नमस्कारः केशवं प्रति गच्छति || AkAshAt patitam tOyam yathA gacchati sAgaram | sarva dEva namaskArah kEshavam pratigacchati || Interpretations: Literal meaning: As all the raindrops falling from the sky ultimately meet their end in the ocean, the worship of any divine God ultimately reach the one Supreme Lord.
Essentially, a nincompoop is a fool, a stupid person whose incompetence or naïveté is quite apparent. It is often used to describe people of a much lower social ranking, although some may describe an unpopular or incompetent leader as an "utter nincompoop." It is conceivable that the originator of "nincompoop" was seeking to combine several unsophisticated words into one nonsensical but descriptive word.