hints are for the word alone, they don't take the whole sentence into consideration. However, most of the times the top hint on the list is the most appropriate word.
Realizing this has helped me so much! Thanks for saying it's usually true, djeidot.
Yeah on this hint it isn't mentioned. It is on the other sentence involving "Eu uso..." though. That's weird
It's a verb. Verbs don't have gender. They follow conjugations based on the subjects:
Eu usO / Tu usAS / Ele(a) usA / Nós usAMOS / Vós usAIS / Eles usAM