Don't look a gift horse in the mouth

[AndiFlatland]

Does anybody know the origin of this expression?
Why a "gift Horse"?

Also, any idea why, if the plural of goose is geese, then why is the plural of mongoose not mongeese?

[auntflo]

i think you can tell a horse's age by looking at it's teeth, so if someone is kind enough to give you a horse and you look in it's mouth, then you are questioning the quality of the present (old horses are worth less than young horses).

[Quizmonster]

For the same reason that the plural of moose isn't meese, the plural of noose isn't neese and, in Scotland, the plural of hoose isn't heese!

[Quizmonster]

On a more serious note, I should have added above that the word comes from Indian languages such as Marathi and Telugu, so there never was any need for it to have an anglicised plural form to chime with goose/geese. Accordingly, we just added the usual pluralising s.

[Clanad]

So... we've had an excellent explanation of the meaning of the phrase as well as the usual exoteric synthesis of complex information distilled to it's clear understandability re: moose/meese, a goose/geese, sans mon, from the inveterate Q. However, mysteriously, His Inveterateness and auntflo failed to answer the question as to origin(s)...
The phrase is a Probverb; as stated, this proverb is based on the fact that a horse's value is determined by his age, which, in turn, can be roughly determined by an examination of his teeth. The message conveyed is that a gift should be appreciated for the thought and spirit behind it, not according to its value. St. Jerome, (ca. AD400) who never accepted payment for his writings, first used the phrase in reply to his literary critics. His exact words: "Never inspect the teeth of a gift horse." (Source: Trivia-Source).

[jno]

of course, it may not be good advice, Clanad - the Trojans followed it and where did it get them?

[Clanad]

Is it possible jno, that the Trojans were looking at the gift in the wrong way, hence another proverb from the ancient Greeks: Απ' έξω κούκλα κι από μέσα πανούκλα."
"Outside a beautyl, inside the plague."

[jno]

yes, perhaps their failing was inability to speak classical Greek...

[terambulan]

If your given a horse and it has 4 legs, a good back, head a tail it can be used in so many ways and willingly do your bidding....then don't look in its mouth (usually the way to age a horse).

[dundurn]

As handed out to students at the Dick Vet in the '60s

The Age of a Horse
by O. R. Gleason

To tell the age of any horse
Inspect the lower jaw, of course.
The six front teeth the tale will tell,
And every doubt and fear dispel.

Two middle nippers you behold
Before the colt is two weeks old.
Before eight weeks two more will come;
Eight months the corners cut the gum.

The outside grooves will disappear
From middle two in just one year;
In two years from the second pair;
In three years "corners," too, are bare.

At two the middle "nippers" drop.
At three the second pair can't stop.
When four years old the third pair goes.
At five a full new set he shows.

The deep black spots will pass from view
At six years from the middle two;
The second pair at seven years;
At eight the spot each corner clears.

From middle "nippers" upper jaw
At nine the black spots will withdraw.
The second pair at ten are bright;
Eleven finds the corners light.

As time goes on, the horsemen know,
The oval teeth three-sided grow.
The old horse has more "whoa" than "get"
We keep him only for a pet.