curve, fold, hollow
If someone makes an insinuation, they say something bad or unpleasant in a sly and indirect way.
Something that is sinuous is shaped or moves like a snake, having many smooth twists and turns that can often be highly graceful.
ratio of the adjacent side to the hypotenuse of a right-angled triangle
introduce or insert (oneself) in a subtle manner
of or relating to introducing or inserting (oneself) in a subtle manner
ratio of the length of the side opposite the given angle to the length of the hypotenuse of a right-angled triangle
an abnormal passage leading from a suppurating cavity to the body surface
Differentiated vocabulary for your students is just a click away.