Skim
SKIM, noun (a different orthography of scum;
Scum; the thich matter that forms on the surface of a liquor.
SKIM, verb transitive
1. To take off the thick gross matter which separates from any liquid substance and collects on the surface; as, to skim milk by taking off the cream.
2. To take off by skimming; as, to skim cream.
3. To pass near the surface; to brush the surface slightly.
SKIM, verb intransitive
1. To pass lightly; to glide along in an even smooth course, or without flapping; as, an eagle or hawk skims along the etherial regions.
2. To glide along near the surface; to pass lightly.
3. To hasten over superficially or with slight attention.
They skim over a science in a superficial survey.