tensar
tighten
tense
tense, tight
+
-ar
verb suffix
Tensar means to tighten and can be thought of as tense0 (tight0) + -ar1 (verb suffix1).
verb
  1. tighten
    To tighten or make tense
    Necesitas tensar la cuerda del arco. // You need to tighten the bowstring.