This is the 10301st most frequent Spanish word.
complicadas
Complicated.
Here, 'complicadas' functions as an adjective describing the noun 'instrucciones', meaning they are not easy to understand or follow.
Las instrucciones para ensamblar este mueble son complicadas.
The instructions for assembling this furniture are complicated.
In this sentence, 'complicadas' is again an adjective, referring to the challenges and complexities often found in interpersonal relationships.
Las relaciones humanas pueden ser muy complicadas.
Human relationships can be very complicated.
Although 'complicadas' as used previously isn’t in this particular sentence, the word 'complicado' is its singular masculine form, showing adjective agreement based on the gender and number of the noun it describes, 'tema'.