I always thought the term Cop was used because police officers had copper badges and cop was short for coppers...but I just heard that it was British meaning to grab or nab, which is it? Thanks!
Cop - '1704, northern British dialect, "seize," perhaps from M.Fr. caper "seize, to take," from L. capere "to take" (see capable); or from Du. kapen "to take," from O.Fris. capia "to buy." Cop out (v.) and cop-out (n.) are Amer.Eng., first recorded 1942, probably from cop a plea (c.1925) "plead guilty to lesser charges."'
We still say (though now jokingly) " It's a fair cop" meaning a fair and justified arrest (seizing) and so in light- hearted conversation " I admit it. I was lying" or " You've caught me out !" And we say " Cop a look at that !" meaning " Take or grab an eyeful of what I'm looking at !". We also say, often to naughty children, " You won't half cop it!" [if you are seen misbehaving] the image being of getting , catching, a load of trouble , a punishment. That can also be a soldier's euphemism for 'to die', specifically in battle. There must be many other examples in British usage.
A copper is someone who cops someone. That's what a policeman does and this slang term for a policeman dates from the mid C19.How the numerous other slang terms for one e.g 'rozzer' originated is sometimes less clear
