"Ill" is correct; "disdainfully" is an adverb, so it can't be any kind of adjective!
Think of predicate adjectives as words that are describing the subject from the other side of the linking verb.
Here are some examples:
He is tall. ("tall" modifies "He")
The book is old. ("old" modifies "book")
There are some words in addition to forms of the verb "to be" that can be linking verbs -- to seem, to look, etc.
http://grammar.ccc.commnet.edu/grammar/verbs.htm#linking
I cannot tell which is a predicate adjective:
He looks ill today.
He looks disdianfully at the pile of laundry.
Ill or Disdainfully?
2 answers
thank you so much!!!