There are literary hundreds of Latin words in all European languages and we can easily trace their origins back to the times when Roman legions were making way for the civilization as we know it. But do not worry, this list will not contain this kind of words. We will focus only on really ancient ones here.
NOTE: This is by no means a definite list, just a quick scan of BASIC Latin dictionary, and I purposely avoided all those words that are not obvious cognates but could possibly be related. Slavic words are based on the Serbian language, but most of the words are common for all Slavs.
MARE – MORE (SEA) IGNEUS – OGANJ (FIRE) ULIGO – VLAGA (HUMIDITY)
MUS – MISH (MOUSE) AGNIS – JAGNJE (LAMB), OVIS – OVCA (SHEEP)
OCULUS – OKO (EYE), POLLEX – PALAC (THUMB) CRUOR – KRV (BLOOD)
MOLO – MLETI (MILL, TO GRIND) STO – STOJATI (TO STAND), SEDEO – SEDETI (TO SIT), VIDEO – VIDETI (TO SEE), ITIO – ICHI (TO GO) SECCARE – SECHI (TO CUT), PROSECO – PRESECHI (TO CUT OFF)
LAEVUS – LEVI (LEFT) DOMUS – DOM (HOME) TU – TI (YOU), TIBI – TEBI (TO YOU) OLEUM – ULJE (OIL) PRAE – PRE (BEFORE), PROD – PRED (IN FRONT), PROVIDUS – PROVIDJENJE (PROVIDENCE) CASTUS – CHIST (PURE), CASTITAS – CHESTITOST (MORAL PURITY)
POLIS (CITY) – POLJE (FIELD)
This is where it gets really interesting. In Latin “Polis” means “city”, but in Slavic “polje” means “field”. Constantinople for example, is called “Konstantinopolj” in Slavic and these words are obvious cognates. However, the Roman goddess of pastures is “Pales”, which does not make any sense, unless related to the Slavic meaning of “field”.
Goddess Pales: https://en.wikipedia.org/wiki/Pales
SUUS, (but in gen, dat, voc and nom SVAE) – SVOJ (of oneself, belonging to oneself, his own, her own, his, her, its, their)
SUM – SAM (I AM), EST – JESTE (IT IS)
In both of these words we see that Slavic form is more complex, as “sam” is just a short form of “jesam” (I am). It is therefore impossible that Slavs took this word from Latin.
LUX – LUCH (LIGHT), NOX – NOCH (NIGHT)
Now, we know that letter “X” came to Latin via Greek “Chi”, where it was (apparently) pronounced “Kh”. This means that if we read Latin with original Greek pronunciation we get very close to Slavic words. (!) This sound is very typical for Slavic languages and in all other words on this list I marked it as “CH”. In Balkans, unlike in Russia and Ukraine, it is actually two sounds of different softness (Ч + Ћ). Also, it seems that this was not only a pre-Roman sound. It can still exists today in Italian and Spanish (ie. buena noches in Spanish)
Letter Chi: https://en.wikipedia.org/wiki/Chi_%28letter%29
And while the etymology of the word “lux” in Latin is not known, the Slavic one is related to the wood of the pine tree that is drenched in resin. When the wood is cut it excretes resin in order to heal itself. This type of wood is perfect for starting the fire, as it is easy to light and it burns for a very long time. The word “luchiti” in Slavic means “to drench, secrete”, and because of this particular wood, the light is called “luch”. Here is the Wikipedia article about luch (only in Serbian unfortunately).
Note that this type of parallel cannot be drawn from the Latin, where the word resin is of the same root as English – resina, but there is another word – lac, for which English etymological dictionary says the following:
lac (n.) “red resinous substance,” 1550s, perhaps immediately from Middle French lacce, displacing or absorbing earlier lacca (early 15c.), from Medieval Latin lacca. All these are from Persian lak, from Hindi lakh (Prakrit lakkha), from Sanskrit laksha “red dye,” which is of uncertain origin.
Extraction of luch from Pinus nigra, Wikipedia