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desastre m. (Noun) "disaster"

Borrowed from Old Occitan desastre 'id.' From des- "off" (see des-) and astre "star" (see estrella). Based on a belief that an unfavorable alignment of stars boded poorly for one's fate.
desayunar (Verb) "to have breakfast"

Late 15th cent. Literally to break one's fast. From des- "off" and ayunar.
desayuno m. (Noun) "breakfast"

18th cent. From desayunar. Excepting parts of Latin America, the word has replaced the original word for lunch: almuerzo.
descansar (Verb) "to rest"

15th cent. From des- "off" and cansar.
descanso m. (Noun) "break"

Very late 15th cent. From descansar.
descuajar (Verb) "to dissolve;" "to uproot;" "to dishearten"

13th cent. From des-, an opposition suffix, and cuajar (1).
descuajaringar (Verb) "to break into pieces;" (used hyperbolically) "to be exhausted"

From the verb descuajar.
desde (Preposition) "from," "since"

12th cent. merger of Old Spanish phrase des de "from out of." As a phrase des de, first attestation occurs in the 11th cent. Des is from Latin de ex "from within" (see de and ex for relevant etymologies).

Romance: Western Vulgar Latin: Asturian dende, Portuguese des, Catalan des, French dès, Italian da

Vulgar Latin had a number of common 'de ex' phrases that fossilized and compounded into new words over time: Modern Spanish despues, Old Spanish desi, desent.
des-, dis- Prefix indicating the opposite or the negation.

From Latin dis-, a negating prefix but in some instances could mean "utterly" (for example, in the case of dirección) or "asunder." From Proto-Italic *dis 'id.' From Proto-Indo-European *dis "apart."

Indo-European: Germanic: Old High German zi "apart," Old English te- 'id.;' Albanian: ç- "apart;" Hellenic: Ancient Greek διά (diá) "in two"
desear (Verb) "to desire"

12th cent. A verb formed from the noun deseo.