The answer is GOAD, four letters. Treat this as a family rather than a single word, since PROD and SPUR also take four squares and read just as naturally. The bigger decision comes first, though. Urge is both a verb and a noun, and if the puzzle wants the noun you are looking at ITCH, YEN or DESIRE instead.
Verb or noun decides everything here
As a verb, to urge is to push someone else into doing something. As a noun, an urge is a pressure you feel from the inside with nobody pushing at all. The bare clue gives you no way to tell, since the word is spelled identically in both jobs, and nothing should go into the grid until a crossing arrives. A helpful shortcut: the verb fills are almost all consonant heavy and blunt, while the noun fills are short and vowel led. A Y in three squares is YEN. An opening I in four is ITCH.
Inflected clues remove the ambiguity for you, so read the ending carefully. Urged has to produce a past tense, which rules out every noun in the list and gives GOADED or PRODDED. Urges can still go either way, since the spelling covers a plural noun as well as a conjugated verb, but it does at least guarantee a final S. Urging wants a participle. And a clue reading strong urge or sudden urge has committed to the noun outright, which sends you to ITCH, YEN or IMPULSE depending purely on the square count.

A goad was a real object before it was a metaphor
A goad is a stick with a point on the end, used to drive cattle forward from behind. That is the whole thing, and the word survives in the King James phrase about kicking against the pricks, which describes an animal hurting itself by backing into the very implement that is moving it. SPUR works the same way, being a spike on a rider’s heel, and PROD is simply the poke itself with no tool named.
English has taken all three of these physical implements and turned them into verbs about persuasion, which is why they carry a faint edge of irritation. You goad someone by needling them until they move. That is not the same act as encouraging them, and good clues respect the difference.
Egg on comes from edge, not breakfast
EGGON, entered as five unbroken letters, is a regular in this clue’s territory, and the phrase has nothing to do with eggs. The verb came into English from Old Norse eggja, meaning to incite, and it shares its root with the word edge. The breakfast egg is a completely separate word that happens to have landed on the same spelling. Constructors like EGGON because it is five extremely common letters in a useful order, so expect it whenever the clue reads urge on rather than plain urge.
Slot by slot, from three squares to seven
| Letters | Answer | Verb or noun |
|---|---|---|
| 3 | YEN | Noun, a craving |
| 4 | GOAD, PROD, SPUR, PUSH | Verb, applying pressure |
| 4 | ITCH | Noun, a restless want |
| 5 | EGGON, IMPEL, PRESS | Verb |
| 6 | EXHORT, INCITE | Verb, formal or inflammatory |
| 6 | DESIRE | Noun |
| 7 | IMPLORE, ENTREAT | Verb, begging rather than driving |
| 7 | IMPULSE | Noun, a sudden one |
When the clue wants pressure without force
The longer fills are not spare parts, they are different temperatures. EXHORT is verbal and elevated, the word for a speech delivered to a crowd who are supposed to go and do something afterwards. INCITE has drifted so far toward the criminal that modern clues nearly always use it with riots or violence in the surface. IMPLORE and ENTREAT invert the direction entirely: they are pressure applied from below by someone with no power, which is the opposite of a goad. IMPEL is the coldest of them, describing a force acting on a person rather than a person persuading another, and it comes from the same Latin verb for driving that gave English compel and propel. Match the temperature of the clue and the length table stops being a guessing game.
Frequently asked questions
What is the three letter answer for Urge?
YEN, and it only works for the noun sense. If your crossings show a three letter slot here, the puzzle is asking about a craving rather than about persuading anyone.
What is the difference between GOAD and PROD?
A prod is a single nudge, while goading is sustained and deliberately irritating. Clues that mention needling, taunting or provoking point to GOAD.
Does Urge on change the answer?
Yes, and helpfully so. Urge on rules out every noun fill and points at EGGON or SPUR, both of which mean driving someone forward rather than feeling a want.