| Answer | Crossword Clue |
|---|---|
| RAREFY | Make less dense |
| RAREFY | Make less dense. |
| RAREFY | Make thin or less dense. |
| SMARTER | Less dense |
| CLEVERER | Less dense |
| AIRIER | Less dense |
| SPARSER | Less dense |
| RAREFIES | Makes less dense |
| THINNED | Got less dense |
| THINS | Makes less dense |
| RAREFY | Become less dense |
| RAREFY | Become less dense. |
| THINS | Becomes less dense |
| THINNED | Became less dense. |
| OPAL | It's less dense than quartz |
