The Spanish word 'decepción' comes from the Latin 'deceptio' meaning 'deception', which itself derives from the Latin verb 'decipere' meaning 'to deceive'. The verb 'decipere' was formed by combining two Latin elements: the prefix 'de-' meaning 'down, away' and the verb 'capere' meaning 'to take or seize'. So literally, the original meaning was something like 'to take away' or 'to catch by deception', which evolved to mean 'to deceive' and then specifically 'disappointment' in Spanish.

It's interesting to note that while the English cognate 'deception' maintains the meaning of trickery or fraud, the Spanish 'decepción' has evolved to primarily mean 'disappointment', though it can sometimes also carry the meaning of deception.

Some related Spanish words include 'decepcionar' (to disappoint), 'decepcionante' (disappointing), and 'decepcionar' (to deceive). These all share the same Latin root and follow similar patterns of meaning related to disappointment or deception.

English speakers can easily remember 'decepción' by connecting it to the English word 'deception', though they should be careful to note the difference in meaning. Other related English words include 'deceive', 'deceptive', and 'deceit', all of which come from the same Latin root 'decipere'. The word 'captive' and 'capture' are also distantly related, as they come from the Latin 'capere' (to take or seize) which forms part of the etymology.