thought vs whimsey

thought and whimsey both are nouns.

Word	Noun	Adjective	Verb	Adverb
thought	Yes	No	No	No
whimsey	Yes	No	No	No

As nouns, whimsey is a hyponym of thought; that is, whimsey is a word with a more specific, narrower meaning than thought:

thought (noun)	whimsey (noun)
the process of using your mind to consider something carefully	the trait of acting unpredictably and more from whim or caprice than from reason or judgment
the content of cognition; the main thing you are thinking about	an odd or fanciful or capricious idea
the organized beliefs of a period or group or individual
a personal belief or judgment that is not founded on proof or certainty