〜ほど〜ない hodo ~ nai
〜ほど〜ない（hodo ~ nai）means “not as ... as ~ (comparison)”. 「Aは Bほど〜ない」 says A does not reach the degree of B; that is, A is less ~ than B. Formation: N＋ほど〜ない（A は B ほど〜ない）
not as ... as ~ (comparison)
N4Formation
N＋ほど〜ない（A は B ほど〜ない）
Explanation
「Aは Bほど〜ない」 says A does not reach the degree of B; that is, A is less ~ than B. The thing after ほど is the standard you fall short of, and the predicate is negative.
Examples
Note
The predicate must be negative; you cannot say 「Bほど〜だ」 in the affirmative to mean this. It implies both A and B have the quality, but A to a lesser degree.
FAQ
〜ほど〜ない — what does it mean and how is it used?
not as ... as ~ (comparison). 「Aは Bほど〜ない」 says A does not reach the degree of B; that is, A is less ~ than B. The thing after ほど is the standard you fall short of, and the predicate is negative.
〜ほど〜ない — how do you form it?
N＋ほど〜ない（A は B ほど〜ない）
〜ほど〜ない — any usage notes?
The predicate must be negative; you cannot say 「Bほど〜だ」 in the affirmative to mean this. It implies both A and B have the quality, but A to a lesser degree.