noun
ideological slant; intellectual character; aspect of thought
Refers to the underlying ideology, philosophical bent, or intellectual quality of a work, person, or movement. Often used in critical or analytical contexts.
この小説は思想性が強い。
This novel has a strong ideological slant.
彼の作品には深い思想性が感じられる。
One can feel a deep intellectual character in his works.
Compound of 思想 (thought, ideology) and 性 (nature, quality). The exact historical derivation is uncertain, but the word follows a common pattern for abstract nouns describing a characteristic quality.