An adjective modifies noun or pronoun i.e. highlights some of the properties of noun or pronoun. In Punjabi, adjectives usually precede the nouns but follow the pronouns.
For example:

ਸੋਹਣਾ sōhṇā handsome
ਕਾਲ਼ਾ kāḷā black
ਹਰੀ harī green
ਨੀਲੀ nīlī blue

Above are functioning as adjectives in ਸੋਹਣਾ ਮੁੰਡਾ, ਕਾਲ਼ਾ ਘੋਡ਼ਾ, ਹਰੀ ਬੱਸ, ਨੀਲੀ ਕਾਰ respectively.
As mentioned earlier, various pronouns can act as adjectives modifying nouns in sentences. Therefore, if a pronoun is modifying a noun then it will be termed as adjective. 


Punjabi adjectives can be classified into two types – Inflected and Uninflected, depending upon whether they change forms for number and case or not. This classification is also referred to as ਕਾਲ਼ਾ and ਲਾਲ respectively. Class of ਕਾਲ਼ਾ adjectives can change forms. Class of ਲਾਲ adjectives do not change forms for number and case.
On the semantic basis, adjectives are of five types: Qualitative adjectives, Numeral (cardinal and ordinal) adjectives, Quantitative adjectives, Demonstrative adjectives and Possessive or Pronominal adjectives.

Inflected Adjectives: These adjectives behave like nouns i.e. have assigned gender and change forms for number and case. E.g. ਸੋਹਣਾ, ਕਾਲ਼ਾ, ਗੋਰਾ are all inflected adjectives for masculine gender and ਸੋਹਣੀ, ਕਾਲ਼ੀ, ਗੋਰੀ are corresponding forms for feminine gender. So inflected adjectives can be either masculine or feminine. /-ਆ/ ending adjectives are the masculine and their/-ਈ / ending forms are the feminine. For example :-

ਸੋਹਣਾ sōhṇā handsome ਸੋਹਣੀ sōhṇī beautiful
ਕਾਲ਼ਾ kāḷā black ਕਾਲ਼ੀ kāḷī black
ਗੋਰਾ gōrā fair-complexioned ਗੋਰੀ gōrī fair-complexioned


Inflected adjectives change forms for number and case.

  /-ਆ/ ending and /-ਈ / ending Inflected adjectives inflect for the number grammatical category. Plural forms of /-ਆ/ ending singular adjectives are /-ਏ/ ending and plural forms of /-ਈ / ending singular adjectives are /-ਈਆਂ/ ending. For example :-

ਸੋਹਣਾ sōhṇā handsome ਸੋਹਣੇ sōhṇē handsome
ਸੋਹਣੀ sōhṇī beautiful ਸੋਹਣੀਆਂ sōhṇīāṃ beautiful

Case:   As mentioned earlier, inflected adjectives take forms like Punjabi nouns. However, only direct and oblique case forms are generally used. Vocative case forms may be used in specific contexts. For example direct and oblique case forms of masculine adjective ਸੋਹਣਾ are: 
ਸੋਹਣਾ sōhṇā singular ਸੋਹਣੇ sōhṇē singular
ਸੋਹਣੇ sōhṇē plural ਸੋਹਣਿਆਂ sōhṇiāṃ plural

Direct and oblique case forms of feminine adjective ਸੋਹਣੀ are:
ਸੋਹਣੀ sōhṇī singular ਸੋਹਣੀ sōhṇī singular
ਸੋਹਣੀਆਂ sōhṇīāṃ plural ਸੋਹਣੀਆਂ sōhṇīāṃ plural

Uninflected adjectives:   This class of adjectives do not change form for gender, number and case. For example: 

ਲਾਲ lāl red
ਮਿਹਨਤੀ mihnatī hard-working
ਮਸ਼ਹੂਰ mashhūr famous
ਦਿਲਚਸਪ dilcasap interesting