It is a vulgarized version of "tronido" ("thunder sound"), which today is understood as something that impresses, that leaves stunned and is said by grace, elegance that is shown, and also by arrogance.
It means elegance, brilliance, lordship, gallantry. Make note of good qualities (highlight the category, reflect elegance). Ostentation, arrogance.
TRONIO:LUCIMIENTO, GALLANTRY, LORDSHIP AND ELEGANCE OF A PERSON.