see below An adjective complement is a phrase or clause that modifies an adjective or adds to its meaning

see below

An adjective complement is a phrase or clause that modifies an adjective or adds to its meaning. An adjective complement may be a prepositional phrase or a noun clause.

Examples

Prepositional Phrase as Adjective Complement:

Larry is generous to his nephews and nieces.

She is curious about his .

Everybody was happy for his success .

Noun Clause as Adjective Complement:

Ira was so thankful that she passed the entrance examination.

I am very happy you are finally settling down.

Everybody was disappointed that she quit the contest.