The comparative form of adjectives are typically classified into three degrees: comparative of superiority (e.g. “more beautiful”), comparative of equality (e.g. “as beautiful as”) and comparative of inferiority (e.g. “less beautiful”). There are two ways to construct comparative forms: morphological (i.e. with suffixes) and syntactic (i.e. with adverbs). The comparative of inferiority expresses that one referent has a property to a lower degree compared to the other referent(s). Both in Persian and English, there is no morphological way to construct the comparative of inferiority. Both languages use adverbial constructions for this purpose.

In Persian, the comparative of inferiority is not as common as it is in English. For instance, instead of “less expensive”, we tend to use the superior degree of the opposite adjective (“cheaper”) or the negated form of its equality degree (“not as expensive as”).

Gold is less expensive than platinum
طلا کمتر از پلاتین گران است
⟨talâ kamtar az pelâtin gerân ast⟩
(using an adverbial structure: “less” + “adjective”)
طلا ارزانتر از پلاتین است
⟨talâ arzântar az pelâtin ast⟩
(using the superior degree of the opposite adjective)
طلا به گرانی پلاتین نیست
⟨talâ be gerâni-ye pelâtin nist ⟩
(using the comparative of equality with a negative verb)

The first sentence literally translates to “Gold less than platinum expensive is”. That is, “less” + “adjective” are separable as opposed English, where “less expensive” is an inseparable unit. The first sentence can be alternatively worded as follows, which is closer to its English equivalent.

Gold is less expensive than platinum
طلا از پلاتین کمتر گران است
⟨talâ az pelâtin kamtar gerân ast⟩
(literally: “Gold than platinum less expensive is”)