osar
dare
ostentatious
showy, bold
+
-ar
verb suffix
Osar means to dare and can be remembered by thinking of someone ostentatious0 (showy or bold0) enough to dare, plus the -ar1 verb ending1.
verb
  1. dare
    To dare or have the courage to do something
    No osó decir la verdad. // He didn't dare to tell the truth.