[5] The racket-tipped thorntail was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

[6] Gmelin based his description on the "L'oiseau-mouche à raquettes" that had been described by the French polymath Georges-Louis Leclerc, Comte de Buffon in 1779 in his Histoire Naturelle des Oiseaux.

[7] Buffon did not specify the origin of his specimen but in 1902 Hans von Berlepsch and Ernst Hartert designated the type locality as Cayenne, French Guiana.

[8][9] The racket-tipped thorntail is now placed with four other hummingbirds in the genus Discosura that was introduced in 1850 by the French naturalist Charles Lucien Bonaparte.

Beginning in 2019 taxonomic systems gradually changed the name to match that of the other members of genus Discosura, which are all called "thorntail".

Their tail is long and mostly purplish; the outer pair of feathers are much longer and end in a wide blackish "racket".

[16][17][18][19][20][excessive citations] Martin Johnson Heade depicted two coquettes in his painting Two Green-Breasted Hummingbirds (c. 1863), as part of his "Gems of Brazil".

[16][17][18][19][20][excessive citations] The racket-tipped thorntail is generally a year-round resident throughout its range[16] though is only known seasonally in parts of Venezuela[19].

"[19] The racket-tipped thorntail feeds in the forest canopy, taking nectar from a variety of flowering trees both native and introduced.

As of August 2024 the Cornell Lab of Ornithology's Macaulay Library had no recordings of racket-tipped thorntail vocalization.