Something underrated is better than most people realise. An underrated film, an underrated player, sleep is underrated.
It is the friendlier half of a pair with overrated, and it is used far more generously — calling something underrated is a way of recommending it while suggesting you noticed first. The construction is usually predicative: it is underrated. The phrase hugely underrated is almost a fixed unit. Note that the claim is about other people's judgement rather than about the thing, which is what makes it so easy to say and so hard to argue with.
1adjectiveunderratedBetter or more important than most people recognise.
“It is a hugely underrated part of the job.”
synonyms: undervalued, unappreciated
underrated is a judgement of reputation.
From under- + rated.
Etymology from Wiktionary, CC BY-SA