Yes, loose is a Scrabble word!

Adverb

1. Without restraint

Adjective

1. Not compact or dense in structure or arrangement

2. (of a ball in sport) not in the possession or control of any player

3. Not tight; not closely constrained or constricted or constricting

4. Not officially recognized or controlled

5. Not literal

6. Emptying easily or excessively

7. Not affixed

8. Not tense or taut

9. (of textures) full of small openings or gaps

10. Lacking a sense of restraint or responsibility

11. Not carefully arranged in a package

12. Having escaped, especially from confinement

13. Casual and unrestrained in sexual behavior

Verb

1. Grant freedom to; free from confinement

2. Turn loose or free from restraint

3. Make loose or looser

4. Become loose or looser or less tight