| In the U.K., 1.0567 liquid quarts | 33 |
| In the U.S., it has more than 950 stations | 42 |
| In the work already mentioned: Abbr. | 36 |
| In the year before Christ: Abbr. | 32 |
| In the __ (at one's best, in sports) | 40 |
| In the __: part of the inner circle | 35 |
| In the ___ (firing on all cylinders) | 36 |
| In the ___ breath (almost simultaneously) | 41 |
| In the ___ the gods (left to fate) | 34 |
| In this race, the runners are always behind | 43 |
| In this, a "." is a "dot" | 45 |
| In this, a "." is a "period" | 48 |
| In this, a "." is a "point" | 47 |
| In this, following directions is mandatory | 42 |
| In those days (with "back") | 37 |
| In triplicate, a Seinfeld catchphrase | 37 |
| In trouble, with "off" | 32 |
| In two pieces, like two-by-fours | 32 |
| In uncharted territory, so to speak | 35 |
| In use, as an apartment building | 32 |
| In vogue, or words after "all" | 40 |
| In what country are Panama hats made? | 37 |
| In which a CPA writes tentatively? | 34 |
| In which a long run leads to home | 33 |
| In which a queen is most powerful | 33 |
| In which Christmas comes but once | 33 |
| In which Horatio accosts a ghost | 32 |
| In which King was once the queen | 32 |
| In which Taylor was rough and ready | 35 |
| In which the Balcony Scene takes place | 38 |
| In working order, as a vending machine | 38 |
| In ___ (archaeologist's phrase) | 35 |
| In ___ (at the pawnbroker's) | 32 |
| In ___ (faced with a predicament) | 33 |
| In ___ (how location-specific art is viewed) | 44 |
| In ___ (in its original position) | 33 |
| In ___ (Latin "actually") | 35 |
| In ___ (left where it was found) | 32 |
| In ___ (legalese for original position) | 39 |
| In ___ (matching, as audio and video) | 37 |
| In ___ (stuck in the same old same old) | 39 |
| In ___ (stuck in the same routine) | 34 |
| In ___ (within a living organism) | 33 |
| In ___ of (as a replacement for) | 32 |
| In ___ parentis (legal doctrine) | 32 |
| In ___, plenty of ___ is growing | 32 |
| In ___, you might see some ___ hanging around | 45 |
| In _____ signo vinces (ancient motto) | 37 |
| In-box item on one's birthday | 33 |
| In-flight announcement, for short | 33 |
| In-flight announcements, for short | 34 |
| In-flight entertainment, for short | 34 |
| In-flight guesstimate, for short | 32 |
| In-house computer linkup, briefly | 33 |
| In-state opponent of a 'Cane | 32 |
| In-your-face '50s-'60s talk show host Joe | 49 |
| Inability to distinguish different pitches | 42 |
| Inability to get A's or B's? | 36 |
| Inability to go when others are around | 38 |
| Inability to name everyday objects | 34 |
| Inability to recall the names of objects | 40 |
| Inability to recognize and name objects | 39 |
| Inability to see Fido's neckwear? | 37 |
| Inability to stay focused, briefly | 34 |
| Inability to tell A from B, e.g. | 32 |
| Inaccurate info on many online dating profiles | 46 |
| Inaccurate verb in a toy's name | 35 |
| Inadmissible testimony of a sort | 32 |
| Inadvertently destructive sort, literally | 41 |
| Inadvisable thing to do, usually, in the mail | 45 |
| Inappropriate for high-class Brits | 34 |
| Inappropriate for the easily offended, say | 42 |
| Inappropriately used therapeutic jargon | 39 |
| Inarticulate expression of disbelief | 36 |
| Inaugural baseball Hall of Famer Ty | 35 |
| Inaugural Rock and Roll Hall of Fame inductee | 45 |
| Inc.'s across-the-pond counterpart | 38 |
| Inca ___ (popular Peruvian soft drink) | 38 |
| Incapable of being detected, in a way | 37 |
| Incapable of even trying a combover | 35 |
| Incarcerated leader of the Gambino crime family | 47 |
| Incarceration for certain offenders | 35 |
| Incarnation of the Egyptian god Thoth | 37 |
| Incas' origin, in their mythology | 37 |
| Incas' victims: 15th century | 32 |
| Incendiary fuel in "Apocalypse Now" | 45 |
| Incense (with "stick") | 32 |
| Incessantly contemplate something | 33 |
| Incident involving a missing lab vessel? | 40 |
| Incidentally, in chat room shorthand | 36 |
| Incidentally, in e-mail shorthand | 33 |
| Incidentally, in online shorthand | 33 |
| Incidentally, in texting shorthand | 34 |
| Incite to attack, with "on" | 37 |
| Inclement, as some wintry weather | 33 |
| Inclination to see the glass half full | 38 |
| Include a document, as with an email | 36 |
| Include discreetly a Yankees ace on an e-mail? | 46 |
| Include secretly in an email, say | 33 |
| Include secretly, as in an email | 32 |