Terapéutica was first found in Spanish from 1555 on, when it appeared in Dioscórides, by Andrés de Laguna.
The word terapéutica was taken by Laguna from vulgar Latin therapeutica, -orum (medicine treaties) and from Greek therapeutikós (the occupation of a service man who had to take care of someone, deriving from therapein). In Spanish, this word always had medical care connotation and, more recently, psychological ones. The word terapeuta (therapist) comes from Greek therapeutes (servant).

Jerga means “slang” and its first meaning was “special language, hard to understand” according to the first edition of Diccionario de la Academia (1734). Today it refers to the language that is used specifically by people who belong to a particular group, or profession. For example, la “jerga médica”.

Jerga comes from gergon, which came from Old French jargon or jergon in the Middle Ages and referred to birds chirping.

Jergon was formed by root garg-, which had an onomatopoeic origin, and meant “to speak confusely”, “to swallow” and has evolved into words like garganta (throat), gargajo (gob) and jeringoza (a child’s playful way of hiding language using the letter p and other obscuring devices), among others.

Indigente is someone who is poverty-stricken and usually lives on the streets, has no documents, etc.
Indigente comes from Latin indigens, -entis, from the verb indigere (to lack something), formed by prefix indu- (an old form of –in) and the verb egere (to be deprived of something).

We see an example of use of this verb in the Vulgate:

Qui dat pauperi non indigebit (He who gives to the poor will lack nothing).