From Teflpedia

Wordiness (/wɜ:dinəs/) is using excessive numbers of words to convey a message, particularly in writing. It is generally frowned upon in English and considered a stylistic error.[1]

Student writing often is wordy, particularly if they have a word count to hit and can't think of much to say.

Disparaging wordiness however might be culturally specific, so students might not realise that this is a problem.