出典:Wiktionary
When used as an adjective, less than can never be used attributively, but it is also ungrammatical to use it as a postpositive immediately after the word modified. Rather, it must be used postpositively as part of a complement.
0未満で
less than zero
安上がりの
less expensive
less than acute
spend less
最少量.
ローで.
がっくりした
low-paying
より小さくなる