Juggler*, or older spelling, iugler, was a standard translation of bateleur, for example:
Bateleur, S. Af. a Juggler, i Puppet-player, a Buffoon, a Mountebank...
The Royal Dictionary: Abridged in Two Parts, I French and English, by Abel Boyer, 1728
Bateleur, a juggler, a puppet-player.
A short dictionary of French and English by Guy Miège, 1684. (Also in Nouvelle Grammaire Angloise, 1600)
Bateleur, as basteleur. A iugler, tumbler, puppet-player, one that professeth any of those arts; also, one that leads bears, baboons, or dancing dogs about the country, and gets a secure living by them.
A dictionarie of the French and English Tongues, 1611 compiled by Randal Copgrave.
"Jongleurs It is a word now synonymous to bateleur (a juggler) who plays sleight of hand. Formerly this name was given to a kind of minstrel, who went about singing small poems in the houses of the great, and particularly in the court of the earls of Flanders; but this name was more usually given to a kind of buffoon or juggler, who had succeeded to the historians. The greatest part of them were of Provence; they understood music, and played on instruments. They connected themselves with the Troubadours, or Trouveurs, poets in vogue since the eleventh century, whose productions they sang and performed. By these means they got admittance into the palaces of kings and princes, by whom they were rewarded with magnificent presents. They were also called Jugleurs, Jongleurs and the women Jongleresses."
"At the end of the fourteenth century the Trouveurs and the Jongleurs separated themselves into two bodies; the one under the name of Jongleurs joined singing and the recitation of verses to the sound of instruments; the others under the name of Joueurs (Joculatores) amused the people by sleight of hand &c., like the jugglers of this day. About the time of Philip Auguste the Jongleurs came to disgrace because poetry was little in esteem at that time, more particularly after the death of the count of Champagne, who composed so many amorous verses for queen Blanche. The name of Jongleurs became so contemptible that it was applied only to jugglers, and at length, as they repeated nothing but buffoonery, the term Jonglerie signified falsehood, and they used the words jongler and jaugler to signify to lie. It is for this reason that Philip Auguste drove them from his dominions. They, however, reappeared and were tolerated in the following part of the reigns of this prince and of the kings that succeeded him. They all took the name of Jongleurs, as the most ancient. They lived all in one street then called Rue des Jongleurs, now de S Julien des Menestriers, that is, Street of the Jugglers...
Archaeologia Or Miscellaneous Tracts Relating to Antiquity, Volume 13, 1800
Specifically in reference to Tarot
Samuel Singer refers to it as the Pagad or Juggler:
...the Juggler, or Bateleur... if the Pagad or Juggler is taken, the party taking him also earns five points.
Researches into the history of playing cards, 1811.
Chatto translates it:
The Bateleur, or Juggler; called also Pagad...
Facts and Speculations on the Origin and History of Playing Cards by William Chatto, 1848 edition.
The Journal of Psychological Medicine and Mental Pathological, by Forbes Winslow, 1860 (paraphrasing Levi) writes:
We are instructed that the letter aleph of which the equivalent in Latin and French is A, and the numerical value 1, signifies the candidate the man about to be initiated, the dexterous individual (the card --juggler --le bateleur du tarot).
*Note: the term Juggler had a far more extensive meaning/semantic range than it does today, and referred to public performers of hocus pocus, sleight of hand, cup and ball players, and more in line with what we refer to today as stage magicians rather than jugglers. Also animal trainers/entertainers (with performing bears - monkeys - dogs etc). The English translations of Gebelin that I am aware of are fairly modern, and as the term Juggler/Iugler no longer has the same semantic range as it did, modern translators would probably avoid it in favour of another term, or if a tarot enthusiast choose one that best serves their post-hoc conceptions.