wild ideas; crazy thoughts; fantastical notions
Refers to unrealistic, irrational, or wildly imaginative ideas, often with a slightly literary or emphatic tone. Not an everyday word for 'silly thought'.
His head was full of wild ideas.
その小説は作者の狂想が生み出した世界だ。
That novel is a world born from the author's fantastical notions.
capriccio · wild excitement; frenzy; mania
Compound of 狂 (kyō, 'madness, insanity') and 想 (sō, 'thought, idea'). The exact historical derivation is uncertain, but the meaning is transparent from its components.