cinch 
(sĭnch)
(sĭnch)n.
1.
a. A girth for a pack or saddle.
b. An encircling cord, band, or belt.
2.
a. Something easy to accomplish. See Synonyms at breeze1.
b. A sure thing; a certainty: Their team is a cinch to win the tournament.
v. cinched, cinch·ing, cinch·es
v.tr.
1.
a. To put a saddle girth on (a horse).
b. To secure (a saddle) by means of a cinch.
c. To encircle or wrap tightly: "her hair orderly, her nightgown cinched around her neck" (E. Annie Proulx).
d. To tighten (an encircling cord or belt, for example).
2. Informal To make certain; secure or guarantee: cinch a victory.
v.intr.
To tighten an encircling band or saddle girth. Often used with up.
[Spanish cincha, feminine of cincho, belt, from Latin cīnctus, from past participle of cingere, to gird; see kenk- in the Appendix of Indo-European roots.]