/ɪnˈdɪf.ər.ənt/
[adjective] Not feeling interested in or caring about something or someone. When you are indifferent, something does not seem important or exciting to you — it is neither good nor bad.
Being 'indifferent' once meant being perfectly fair and unbiased — a quality judges were praised for, not criticised.
The word 'indifferent' travels back to the Latin root 'indifferens', which was formed by joining the prefix 'in-' (meaning 'not') with 'differens', the present participle of the verb 'differre'. That verb meant 'to carry apart', 'to scatter', or 'to make a distinction between things', and it was built from 'dis-' (apart) and 'ferre' (to carry or bear). So at its heart, 'indifferent' described something that made no distinction — that did not 'carry things apart' or separate them into better and worse.
In classical Latin, 'indifferens' was largely a philosophical term. Stoic philosophers used it to describe things that were neither good nor bad in a moral sense — things that simply did not matter to the pursuit of virtue. Health, wealth, and pleasure were classified as 'indifferentia' — neutral things, morally speaking. This gave the word a tone not of laziness or coldness, but of calm, balanced wisdom.
When the word passed into Old French as 'indifferent' and then arrived in English in the 14th century, it carried that original sense of neutrality and impartiality. An indifferent judge was actually a good thing — someone who held no favourites, who treated all sides equally. Writers and legal texts praised indifferent arbiters for their fairness. This meaning survived well into the 16th century, and Shakespeare himself used 'indifferent' to mean 'ordinary' or 'moderate' — not quite good, not quite bad, simply in the middle.
Over the course of the 16th and 17th centuries, however, the word began to drift. As English speakers started using it more and more to describe a person who simply did not care — who felt no preference either way — the emotional temperature of the word dropped. Being in the middle was no longer noble neutrality; it began to feel like apathy. The sense of fairness faded, and 'indifferent' increasingly described a person who could not be bothered, whose heart was simply unmoved.
By the 18th and 19th centuries, this cooler, more negative meaning had firmly taken hold. Poets and novelists used 'indifferent' to suggest emotional coldness or social detachment. The word lost most of its old philosophical grandeur and became instead a quiet accusation — a way of saying that someone lacked feeling where feeling was expected. Related words that share the Latin 'differre' root include 'differ' (Latin differre → Old French differer → English differ), 'difference' (Latin differentia → Old French difference → English difference), and 'defer' (Latin deferre → Old French deferer → English defer), though 'defer' carries a slightly different shade from 'dis-ferre' meaning to carry down or away. Each of these words preserves some trace of that original idea of things being carried apart — separated, distinguished, or set at a distance — which is exactly what the indifferent person refuses to do.