Speaking of the word "hard," using it to describe your work tasks can also have a negative effect.
ZipRecruiter hosts a database of more than 3,000,000 résumés, which small businesses, individual employers, and recruiters looking for candidates can rate on a scale of one to five stars (one being the lowest, five the highest). After ZipRecruiter analyzed these résumés and their ratings, it found a correlation between certain keywords and low ratings.
The word "hard" was found to a strong correlation with one-star reviews, with up to a 79% greater likelihood of receiving the lowest rating. It's likely the word gives employers the impression that you're put off by hard work.