The original scavenger was an important official.
There is too the study of semantics—the science of meanings as distinguished from phonetics, the science of sound.
The exchequer is really a chess-board; chancel a cross-bar, so cancel.
The study of metaphors is a little startling, when we find that to "take the cake" is paralleled by the Greek λαβειν τον πυραμουντα, and that "to lose the ship for a ha'porth of tar" is merely dialect for sheep. Tar is used as a medicine for sheep.
Folk etymology is worth spending time over, if only to discover such things as the derivation of humble-pie, a pie made from the umbles of a stag; umpire (non per), not equal; ramper, causeway, a doublet of rampart; purley, a strip of disforested woodland from pour-allée; taffrail from tafel, picture; posthumous, from postumus, latest-born. Witch-elm has nothing to do with witches; it is for weech-elm, the bent elm.
Ignorance of the true meaning of a word leads to vain repetitions: greyhound means hound-hound; Buckhurst Holt Wood means beech wood wood wood; a cheerful face means a face full of face.
And before taking leave of us and sending us off on a thousand different scents of our own in chase of words Professor Weekley warns us to preserve the rules of the hunt. A sound etymology must not violate the recognised laws of sound change (these may be found in Professor Wyld's book); the development of meaning must be clearly traced, and it must start from the earliest or fundamental sense of the word.
With the few delicious examples that I have quoted before you, multiplied by a thousand in The Romance of Words, this is a game to send you into ecstasies, and one of which you can never tire.