Final answer:
The suitable collocation to complete the sentence is 'eager,' which reflects the fans' anticipation and excitement.
Step-by-step explanation:
a collocation is a series of words or terms that co-occur more often than would be expected by chance. In phraseology, a collocation is a type of compositional phraseme, meaning that it can be understood from the words that make it up. This contrasts with an idiom, where the meaning of the whole cannot be inferred from its parts, and may be completely unrelated.
The correct collocation to complete the sentence 'Hundreds of ___ fans were waiting for Shamira to come out of the concert hall.' is eager. Using 'eager' to describe fans emphasizes their anticipation and excitement to see the performer. It is a word that is commonly paired with fans when they are waiting enthusiastically and with great anticipation for an event or a glimpse of their favorite celebrity or performer.