This is a list of Spanish words of uncertain origin. Some of these words existed in Latin and/or Ancient Greek, but are thought by some scholars to ultimately come from some other source. Many of these words have alternate etymologies and may also appear on a list of Spanish words from a different language.
A ademán agachar agalla ají amargo anchoa añicos Apache ardilla areito arete aro arrancar arrear arriero arveja/alverja asustar
B balde (barrel, tub) barato barraca barro bata baúl beso bisagra bizco borrar borrego bronce bruja buitre burla burlar buscar
C cabaña, cacarear caleta cama cambur camilla canica caracol carcajada catalán cataluña cebra celta cagarra changa chango charco chileno chipre chiste chorro chupar cibernética coco cochino, cucubano
D danza derrocar destrozar
E -ez (name suffix)
G gabacho gacho gago gana ganga garbanzo garza gobernar godo gorra gorrión gorro gótico graznar gusano,
H hipo
J judía (lima bean) juey
L lama latir laurel leopardo lerdo lirio water lily liso listo
M malgache malva manteca mantecado mantequilla mascota maullar metralla mimo mimar mohíno moho moneda moño mueca migir
N nabo niña
O ola olivo -ón= augmentative suffix (opposite of a diminutive suffix), as found in balón "big ball.": the same as Italian -one. Examples: guitarrón (from guitarra), salchichón (from salchicha). Exceptions (nouns ending in -ón that are not in the augmentative): aguijón, camarón, empujón.
P pantano pantalla pantera parra parrilla pata patán patear patillas patín patio pato patrulla pavana pelícano peluca pequeño pera pito porrazo prado
S sabotear saeta salpicar salsifí senda sendero sodio soga sucre susto
T titere tonto topar tope trenza trocar tropa tropel troza truco
Z zángano zapato
See also Linguistic history of Spanish List of English words of Spanish origin
References "Breve diccionario etimológico de la lengua española" by Guido Gómez de Silva ()