希薄きはく
kihaku

Noun
na-Adjective

1. thin (air); weak (liquid); dilute; sparse (population); rarefied

たかのぼるにつれて、空気くうき希薄きはくになる。
takakunoboruni tsurete kūkiwa kihakuni naru.
As you go up higher, the air becomes thinner.
Noun
na-Adjective

2. lacking (enthusiasm, consideration, substance, etc.); insubstantial; deficient; tenuous (link)

Other forms: