Comparative adjectives not only express superiority (“more beautiful”) but also, they can express equality (“as beautiful as”) and inferiority (“less beautiful”). Languages like French and Spanish, have clear and universal structures for the three degrees of comparison. In Persian, adjectives do not have a universal structure to express inferiority. For example, there is no direct structure to express “A is less intelligent than B”. It is expressed in other ways e.g. “A is not as intelligent as B” or “A has less intelligence than B”.

Nominal Form of an Adjective

In Persian, you can convert an adjective to a noun by adding the suffix ی (-i). This noun is called the nominal form of the adjective. For example, in the following table, خوبی (goodness) is the nominal form of خوب (good).

Adjective Noun
خوب
khub
good
خوبی
khubi
goodness
بد
bad
bad
بدی
badi
badness

When an adjectives ends in a vowel other than “-e”, the epenthetic consonant “-y-” is added between the adjective and the suffix “-i” to resolve vowel hiatus. When an adjective ends in “-e”, the consonant “g” appears between the adjective and the suffix. This consonant belongs to the older form of the word and is not the result of epenthesis.

Adjective Noun
زیبا
zibâ
beautiful
زیبایی
zibâyi
beauty
تازه
tâze
fresh
تازگی
tâzegi
freshness

Equality structure

To make a comparison of equality e.g. “as good as”, the nominal form of the adjective is placed in the following structure:

Preposition به (“be”) + Nominal form + genitive marker -ye

Since the nominal form of an adjective always ends in the vowel “-i”, the genitive marker “-e” always appears as “-ye” in the above structure.

Examples:

به خوبی
be khubi-ye
as good as
به بدی
be badi-ye
as bad as
به زیبایی
be zibâyi-ye
as beautiful as
به تازگی
be tâzegi-ye
as fresh as

So, for example, به زیبایی (“be zibâyi-ye”) literally means “to the beauty of”.

Equaling A and B

The following structure is used to express a comparison of equality between “A” and “B”.

A equality structure B

Example:

سارا به زیبایی خواهرش است
Sârâ be zibâyi-ye khwâhar-ash ast
Sarah is as beautiful as her sister
Literally, it is like saying: “Sarah’s beauty is equal to the beauty of her sister”