The Collaborative International Dictionary of English v.0.48:

Sinuate \Sin"u*ate\, a. [L. sinuatus, p. p. of sinuare to wind,
   bend, fr. sinus a bend.]
   Having the margin alternately curved inward and outward;
   having rounded lobes separated by rounded sinuses; sinuous;
   wavy.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sinuate \Sin"u*ate\, v. i. [imp. & p. p. Sinuated; p. pr. &
   vb. n. Sinuating.]
   To bend or curve in and out; to wind; to turn; to be sinuous.
   --Woodward.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sinuate
    adj 1: curved or curving in and out; "wiggly lines" [syn:
           sinuate, sinuous, wiggly]
    2: having a strongly waved margin alternately concave and convex