crock: English has two words crock. The one meaning ‘earthenware pot’ [OE] is now almost never heard on its own, except perhaps in the phrase ‘crock of gold’, but it is familiar from its derivative crockery [18]. Its immediate antecedents appear to be Germanic (Dutch, for instance, has the related kruik), but cognate forms appear in other Indo-European languages, including Welsh crochan and Greek krōssós. Cruet [13] comes from Anglo-Norman *cruet, a diminutive frorm of Old French crue ‘pot’, which was borrowed from Old Saxon krūka, a relative of English crock. Crock ‘decrepit person, car, etc’ [15] is earliest encountered (in Scottish English) in the sense ‘old ewe’.
The connotation of being ‘broken-down’, and the existence of near synonyms such as Dutch krak, Flemish krake, and Swedish krake, all meaning ‘wornout old horse’, suggest some kind of link with the word crack. => crockery, cruet
crock (n.)
Old English crocc, crocca "pot, vessel," from Proto-Germanic *krogu "pitcher, pot" (cognates: Old Frisian krocha "pot," Old Saxon kruka, Middle Dutch cruke, Dutch kruik, Old High German kruog "pitcher," German Krug, Old Norse krukka "pot"). Perhaps from the same source as Middle Irish crocan "pot," Greek krossos "pitcher," Old Church Slavonic krugla "cup." Used as an image of worthless rubbish since 19c., perhaps from the use of crockery as chamberpots.