"excited" is a past participle in form (note the -ed ending), but an adjective in function. We know it's functioning as an adjective because the verb is a linking verb. Only adjectives and noun--and some adverbs of place--follow a linking verb. To determine if the verb is linking or not, replace it with the symbol "=", meaning equals, like this,
 (You) = too excited by the sight of your name in print.
 He = very excited to be asked to play for Wales.
 Some horses = excited when they are in traffic.
The basic synax for all of the above looks like this,
Subject: You; He; Some horses
Linking Verb: get; was; become
Subject Complement: too excited; very excited; excited
Note, if the subject complement is an adjective it's called a predicate adjective, and if it's a noun, it's called a predicate nominal.
"excited" is a predicate adjective. That's why your dictionary calls it an adjective. Predicate adjective describe the subject. One way to tell that is to replace the verb with "=":
Max is happy => Max = happy. (Predicate adjective)
Sam was a doctor => Sam = a doctor. (Predicate nominal)
All the best,
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