Horny means to be sexually aroused. Colloquially, however, it is equated with "great" or "super".
"Geil" is one of those words in the German language that can be used in many different ways. Most young people certainly associate this term with something "great" or something impressive. But: only a few decades ago, "geil" was equated above all with sexual excitement.
It is therefore self-explanatory why many older people in particular are often a little shocked these days when they hear about something that is supposedly "horny". At the latest since the word began to play a bigger role in advertising and on TV, however, the tempers about the "youth of today" should have calmed down a bit again.
By the way, "horny" can - despite the extended meaning - still be used wonderfully today for the Dirty Talk are used. Here, many gays (and straights) get turned on by hearing different combinations, such as "You horny sow!". There are almost no limits to the imagination in this area - as is so often the case.
Funnily enough, "horny" is a very old word. Even the Germanic tribes used it to describe something that was "surging" or "foaming". At some point, "geilen" was also used to describe "growing". Nowadays, not much is left of all these meanings. However, it is also certain that the associations are still neutral or positive. Other combinations, such as "horny", however, are classified as swear words. A horny person is someone who would sleep with any partner to satisfy their needs.