This is the 2055th most frequent Russian word.
гуп
The word "гуп" does not have a standard meaning in Russian; it may mimic a sound or be used colloquially/contextually.
In this sentence, 'гуп' is used as an onomatopoeic representation of the sound produced by a ball dropping.
Гуп! Звук упавшего мяча раздался в спортивном зале.
Thud! The sound of the dropped ball echoed in the sports hall.
Here, 'гуп' is referenced as a sound reminiscent of the past experiences, used in a figurative context.
Когда я слышу 'гуп', я всегда вспоминаю нашу старую баскетбольную площадку.
Whenever I hear 'thud', I always remember our old basketball court.
In this context, 'гуп' is described in a didactic manner as an example of auditory depiction in language.