Oxford English Dictionary

Bachelor

The earliest trace of the word is in 1297, when it's original meaning 'A young knight, not old enough, or having too few vassals, to display his own banner, and who therefore followed the banner of another; a novice in arms.'. There is evidence of spelling change too, 'bacheler' and 'bachelere' to point out a few, which may indicate possible change in pronunciation.

We can also see that the word has developed meanings through time. Another meaning refers to 'One who has taken the first or lowest degree at a university, who is not yet a master of the Arts' whilst the more modern meaning of the word relates to the definition'

An unmarried man (of marriageable age)'.

This proves there has been an extension in the word. We may expand one of the more modern meanings to relate a bachelor to an attractive un-married male who has a lot of female interest and has a 'bachelor pad' in the city where he invites females.

Slag

The top definition of the word is A piece of refuse matter separated from a metal in the process of smelting and this was seen from 1552. However as we move into modern times, the meaning of the world evolves and we see the definition of what we would more commonly use the word slag for 'A prostitute or promiscuous woman; a slattern'.


Stud
Defined as A man of (reputedly) great sexual potency or accomplishments; a womanizer, a habitual seducer of women. In weakened uses: as a familiar term of address among men; a boy-friend or escort. This definition has been particularly common 1960, stemmed from c1000 when the word related to   An establishment in which stallions and mares are kept for breeding. Also, the stallions and mares kept in such an establishment, and its etymology is Old English.