| One-eyed Norse deity | 20 |
| One-eyed Norse god | 18 |
| One-eyed overlord | 17 |
| One-fifteenth of CMXV | 21 |
| One-fifteenth of MMMXV | 22 |
| One-fifth of "Hamlet" | 31 |
| One-fifth of 100 | 16 |
| One-fifth of CCCV | 17 |
| One-fifth of CCLX | 17 |
| One-fifth of cinquante | 22 |
| One-fifth of DLV | 16 |
| One-fifth of DXV | 16 |
| One-fifth of DXXX | 17 |
| One-fifth of humankind | 22 |
| One-fifth of MDXXV | 18 |
| One-fifth of MMCCLV | 19 |
| One-fifth of MMDX | 17 |
| One-fifth of MML | 16 |
| One-fifth of MMMDV | 18 |
| One-fifth of MMMV | 17 |
| One-fifth of MMMXXV | 19 |
| One-fifth of MMV | 16 |
| One-fifth of MMXV | 17 |
| One-fifth of MMXX | 17 |
| One-fifth of MV | 15 |
| One-fifth of MXX | 16 |
| One-fifth of Papa Dionne's surprise | 39 |
| One-fifth of quindici | 21 |
| One-fifth of the Union | 22 |
| One-fifth of trentacinque | 25 |
| One-fifth of two bits | 21 |
| One-fifth of XV | 15 |
| One-fifth of zwanzig | 20 |
| One-foot five? | 14 |
| One-foot jumps | 14 |
| One-footer, e.g. | 16 |
| One-footer, say, in golf | 24 |
| One-for-all feeling | 19 |
| One-for-one deal | 16 |
| One-for-one trades | 18 |
| One-for-one transaction | 23 |
| One-for-the-road time | 21 |
| One-for-two deal? | 17 |
| One-fortieth of a maund | 23 |
| One-fourth of a '60s group | 30 |
| One-fourth of a '60s pop group | 34 |
| One-fourth of a 60's group | 30 |
| One-fourth of a barbershop tune | 31 |
| One-fourth of a circle | 22 |
| One-fourth of a Henry Higgins outburst | 38 |
| One-fourth of a shekel | 22 |
| One-fourth of DCXXIV | 20 |
| One-fourth of dodici | 20 |
| One-fourth of forty | 19 |
| One-fourth of MIV | 17 |
| One-fourth of quadri- | 21 |
| One-fourth of this clue's number | 36 |
| One-grained wheat | 17 |
| One-grape wine | 14 |
| One-half and one-half | 21 |
| One-half and three-fourths | 26 |
| One-half base x height, for a triangle | 38 |
| One-half fl. oz. | 16 |
| One-half fluid oz. | 18 |
| One-half of a fl. oz. | 21 |
| One-half of a fluid oz. | 23 |
| One-half of our species, roughly | 32 |
| One-handed a liner | 18 |
| One-handed Norse god | 20 |
| One-hit wonder | 14 |
| One-hit wonder Basil | 20 |
| One-hit wonder born Gabriele Kerner | 35 |
| One-hit wonder named after lead singer Gabriele Kerner's nickname | 69 |
| One-hit wonder of 1984 | 22 |
| One-hit wonder that totally ripped off the Postal Service for its 2009 #1 hit "Fireflies" | 99 |
| One-hit wonder with "Informer" | 40 |
| One-hit wonder, e.g. | 20 |
| One-hit wonder? | 15 |
| One-hit wonders with the 1999 hit "Steal My Sunshine" | 63 |
| One-hit wonders, e.g. | 21 |
| One-horned animal | 17 |
| One-horned beast, for short | 27 |
| One-horned beasts | 17 |
| One-horned fish | 15 |
| One-horse | 9 |
| One-horse carriage | 18 |
| One-horse carriage of India | 27 |
| One-horse carriages | 19 |
| One-horse conveyance | 20 |
| One-horse town | 14 |
| One-horse towns | 15 |
| One-horse vehicle | 17 |
| One-horse vehicles | 18 |
| One-horse ___ | 13 |
| One-horse-too-many town | 23 |
| One-hoss et al. | 15 |
| One-hoss shay man | 17 |
| One-hoss shay's creator | 27 |
| One-hoss shay's owner | 25 |
| One-hoss vehicle | 16 |