| Answer | Crossword Clue |
|---|---|
| INA | "Once ... blue moon." |
| INA | Once ... blue moon. |
| INA | Once .. blue moon |
| INA | Once -- blue moon |
| INA | Once .... blue moon |
| INA | Once ... blue moon |
| RARELY | Once in a blue moon |
| RARE | Once-in-a-blue-moon |
| SELDOM | Once in a blue moon |
| SELDOMLY | Once in a blue moon |
| VERYSELDOM | Once in a blue moon |
| RARITIES | Once-in-a-blue-moon events |
| RARE | Happening once in a blue moon |
| RARE | Seen once in a blue moon |
| SELDOMLY | Once in a blue moon, old-style |
| RARITY | It happens once in a blue moon |
| RARITIES | Things seen once in a blue moon. |
| RARE | Like a once-in-a-blue-moon event |
