curl:  Curl seems to have been borrowed from Middle Dutch krul ‘curly’, and indeed the original English forms of the word were crolle and crulle. The present-day form arose in the 15th century by a process known as metathesis, whereby the sounds r and u were transposed. The Middle Dutch word came from a Germanic *krusl-, source also of German kraus ‘curly’. Modern Dutch krul, meanwhile, has given English cruller ‘small cake of twisted shape’ . => cruller
mid-15c., metathesis of crulle (c. 1300), probably from an unrecorded Old English word or from Middle Dutch krul "curly," from Proto-Germanic *krusl- (cognates: East Frisian krull "lock of hair," Middle High German krol, Norwegian krull, Danish krølle "curl"). The noun is recorded from c. 1600.