The Spanish word 'hipocondríaco' (meaning 'hypochondriac') has its roots in Ancient Greek, where it was formed from two elements: 'hypo' (ὑπό) meaning 'under' and 'khondrion' (χόνδριον) meaning 'cartilage'. These combined to form 'hypochondriakos' (ὑποχονδριακός), which referred to the area under the ribcage where many vital organs are located.

The word then passed through Latin as 'hypochondriacus' and French as 'hypocondriaque' before reaching Spanish. Originally, the term related to the physical area under the cartilage of the ribs, but over time it evolved to refer to someone who is excessively worried about their health, as ancient medicine believed many psychological ailments originated in the organs located in this region.

A related Spanish word is 'hipocondria' (hypochondria), which is the condition itself. You might also encounter 'hipocondrio', which specifically refers to the anatomical region under the ribs - maintaining a meaning closer to the original Greek term.

The English cognate 'hypochondriac' is nearly identical to the Spanish word, both in meaning and form. The English language also uses 'hypochondria' and 'hypochondriacal'. These words followed a similar path through Greek, Latin, and French before entering English, which explains their strong resemblance to their Spanish counterparts.