Yes, hard is in the scrabble dictionary

Hard Definition

adjective

Backed by bullion rather than by credit. Used of currency.

Bad; adverse: hard luck.

Being a turn in a specific direction at an angle more acute than other possible routes.

Bitter; resentful: No hard feelings, I hope.

Chemistry Resistant to biodegradation: a hard detergent.

adverb

Firmly; securely: held hard to the railing.

In such a way as to cause great damage or hardship: industrial cities hit hard by unemployment.

Nautical Completely; fully: hard alee.

Near in space or time; close: The factory stands hard by the railroad tracks.

Toward or into a solid condition: concrete that sets hard within a day.

idiom

Hard and fast Defined, fixed, and invariable: hard and fast rules.

Hard of hearing Having a partial loss of hearing.

Hard of hearing One who has a partial loss of hearing.

Hard put Undergoing great difficulty: Under the circumstances, he was hard put to explain himself.

Hard up Informal In need; poor.