| One trillion, in combinations | 29 |
| One trillionth: Comb. form | 26 |
| One trillionth: Prefix | 22 |
| One tripping over his own feet | 30 |
| One troubled with delusions | 27 |
| One true thing | 14 |
| One trying a hiccups cure | 25 |
| One trying not to make a splash | 31 |
| One trying to avoid a banking crisis? | 37 |
| One trying to avoid charges? | 28 |
| One trying to eliminate bad notes | 33 |
| One trying to find the right combination? | 41 |
| One trying to keep her seat, maybe | 34 |
| One trying to lose | 18 |
| One trying to lose weight | 25 |
| One trying to make a big deal of everything | 43 |
| One trying to make a living? | 28 |
| One trying to make the grade | 28 |
| One trying to make the grade? | 29 |
| One trying to run from home | 27 |
| One trying to shake a leg, for instance? | 40 |
| One trying to slim down | 23 |
| One trying to stay between the lines? | 37 |
| One trying to stay up while going down | 38 |
| One trying to win a hand? | 25 |
| One Tuesday | 11 |
| One turn of an odometer | 23 |
| One turning color? | 18 |
| One turning to enter? | 21 |
| One turning to the right | 24 |
| One TV actor, or two authors | 28 |
| One Twain title character ... | 29 |
| One twelfth of a foot | 21 |
| One twisted cookie? | 19 |
| One twixt 12 and 20 | 19 |
| One two of two-and-two | 22 |
| One tying up a turkey, say | 26 |
| One type contains the alphabet | 30 |
| One type is common | 18 |
| One type of insurance | 21 |
| One type of keyboard ... | 24 |
| One type of message | 19 |
| One type of outdoor flooring | 28 |
| One type of parking | 19 |
| One type of poll | 16 |
| One type of sentence | 20 |
| One type of talk | 16 |
| One type of thermometer | 23 |
| One type of tide | 16 |
| One type of util. | 17 |
| One unable to get a loan, say | 29 |
| One unable to keep a straight face, perhaps | 43 |
| One unaffected by Dutch elm disease? | 36 |
| One under 20 | 12 |
| One under a mattress | 20 |
| One under a mezzo | 17 |
| One under a wing? | 17 |
| One under Manco Capac | 21 |
| One under oath | 14 |
| One under one | 13 |
| One under par | 13 |
| One under, in golf | 18 |
| One undercover | 14 |
| One unhappy about a split | 25 |
| One unhappy with a call | 23 |
| One unhealthy part of cigarettes | 32 |
| One unlike almost any other | 27 |
| One unlikely to be passive-aggressive | 37 |
| One unlikely to bring home the bacon | 36 |
| One unlikely to bring home the bacon? | 37 |
| One unlikely to collaborate | 27 |
| One unlikely to compromise | 26 |
| One unlikely to do a bar mitzvah? | 33 |
| One unlikely to go into Labour | 30 |
| One unlikely to have a cow | 26 |
| One unlikely to make the honor roll | 35 |
| One unlikely to pass the bar | 28 |
| One unlikely to pass the bar? | 29 |
| One unlikely to veg out | 23 |
| One unsatisfied with a "She loves me, she loves me not" result? | 73 |
| One unsuitable for print, e.g. | 30 |
| One unversed in verse | 21 |
| One unwilling to go to bed, say | 31 |
| One unwilling to stand and fight | 32 |
| One up | 6 |
| One up all night at camp? | 25 |
| One up all night in the woods? | 30 |
| One up at all hours? | 20 |
| One up from med. | 16 |
| One up in arms | 14 |
| One up to deviltry | 18 |
| One up, e.g. | 12 |
| One URL ending | 14 |
| One use for a candlestick or wine bottle | 40 |
| One use for a GPS | 17 |
| One use for a high roof | 23 |
| One use for anise | 17 |
| One use for bread | 17 |
| One use for glue | 16 |
| One use for scissors | 20 |