Badly means in a poor way — the opposite of well. A badly parked car, a badly written email, a shelf you put up badly that leans a little to the left.
Its second job is severity: badly hurt, badly damaged, badly beaten, where it means seriously rather than poorly. Its third is plain force — I badly need a holiday, she wanted the part badly — and there it does the work of very much. The comparison is worse and worst, never badlier. After feel, look, sound and taste you want bad, not badly, so it is I feel bad about it. And badly off means short of money, the mirror of well off.
1adverbbadlyIn a poor way; not well.~21%
“The play was badly cast from the start.”
synonyms: poorly
2adverbseriouslySeriously; severely.~77%
“Two passengers were badly hurt.”
3adverbadverbVery much.~2%
“He wanted to win badly enough to train through the winter.”
Shares are an estimate: a language model read 14 sentences found in the wild and placed 14 of them on a sense — a count of our sample, not a measurement of English.
Badly is one of the simplest builds in English: bad with the ending -ly, written baddely and baddeliche in Middle English before the spelling settled. The -ly is the same one that turns quick into quickly. The word was steady on the page long before its meanings finished spreading.
Middle English
badly
English, today
badly
From Middle English badly, baddely, baddeliche, equivalent to bad + -ly.
Etymology from Wiktionary, CC BY-SA