american-englishetymology
What is the origin of using the word "grasshopper" as a term for a neophyte or trainee? The most reliable reference I have is Urban Dictionary, who claims that it is from a 1970's television series called Kung Fu.
I would also be curious to know if this is a term which appears only in American English, or in other countries as well.
OED has
Frequently attributed to D. Vreeland (1906–89), who became fashion editor of Harper's Bazaar in 1937, but compare [an NY Times quotation] (26 February), which cites the March issue of Harper's Bazaar (see below). The term is not found in issues of the Lampoon of that date.
1937 Harper's Bazaar Mar. 116 (heading) Pizazz, to quote the editor of the Harvard Lampoon, is an indefinable dynamic quality, the je ne sais quoi of function; as, for instance, adding Scotch puts the pizazz into a drink. Certain clothes have it, too...There's pizazz in this rust evening coat, swinging wide in back, jutting crazily over the shoulders.
... which does correspond to two of the sources you researched.
It's not unknown for OED to be trumped in its earliest citations, but it does appear to have been coined by Diana Vreeland.
There's a possible 1978 reference to gekkering in a Google Books snippet of The Junior Bookshelf, Volume 42:
David Macdonald is a Scottish zoologist and conservationist whose early work was on red foxes. According to Wikipedia:
He is known for his documentary films and his popular books, for which he has twice won the Natural World Author of the Year award. His Night of the Fox won the BAFTA for Best Documentary Film of 1976, Running with the Fox won the Natural History Book of the Year award for 1987
You can hear some gekkering at 1m11s in this video.
Gekkering isn't in the OED, but perhaps it's related to the Scottish and northern dialects' verb geck:
intr. to geck at : to scoff at, to use mocking language or gestures towards.
Geck's etymology:
apparently < Low German gecken = Middle Dutch ghecken , Dutch gekken , German gecken : see geck n.1, and compare the echoic German gecken to croak, cackle. Also in Scandinavian as Danish gjække, Swedish gäcka.
Best Answer
Kung Fu is indeed the source of this expression. Kung Fu made extensive use of flashbacks to the childhood of the protagonist, Caine, as he learned martial arts from his teacher Master Po, who called his young student Grasshopper as a term of affection. It is mostly used humorously, as a lighthearted comparison of the relationship between the speaker and their less experienced listener with that of wise Master Po and his inexperienced student.
The younger generation might be more likely to use the neologism padawan, which was used similarly in the Star Wars prequels as a name used by Jedi masters for their own young students.