The word should be applicable to a text with too much useless information. Preferably, the term is used in everyday speech, but I wouldn't object against somewhat grandiloquent words.
Since I’m Russian, I can provide you with an example in Russian language, “watery or too much water”(direct translation from Russian, maybe it would help).
Also, looking for a colloquial word for ‘write in a text too many words to pass an assignment(for instance, if you are tasked at school with writing an assignment of 600 words, but you have only 500, and you start adding useless words to hit the threshold of 600).’ Direct translation from Russian is ‘to pour water’.