underfeed

The animal was so underfed that his ribs were showing under his lusterless chestnut coat.
Central Park’s Carriages Saved This Horse|Michael Daly|April 24, 2014|DAILY BEAST
An uneducated, underbred, and underfed propertyless man is a man who has lost the possibility of liberty.
The New Machiavelli|Herbert George Wells
In North Germany, at Ilmenau, we were constantly pained by meeting peasants who looked underfed and miserable.
George Eliot's Life, Vol. III (of 3)|George Eliot
"Nature has no heart," said he, very bitterly and readily, as people do who are over-philosophised and underfed.
In a German Pension|Katherine Mansfield

The pecuniary struggle produces an underfed class, of large proportions.
The Theory of the Leisure Class|Thorstein Veblen
They had been underfed, under-clothed, singled out for all the disagreeable work and all the abuse—because they were English.
Servants of the Guns|Jeffery E. Jeffery

British Dictionary definitions for underfeed

underfeed

verb (ˌʌndəˈfiːd) -feeds, -feeding or -fed (tr)

to give too little food to

to supply (a furnace, engine, etc) with fuel from beneath

noun (ˈʌndəˌfiːd)

an apparatus by which fuel, etc, is supplied from below

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