M : new, un-played, perfect.
M-/NM : like new but carefully played a limited amount of times. Should play perfect with almost no noise or imperfections. May show very faint imperfections from paper scuffs or tiny needle marks.
EX : as above with a few light needle marks, or a few light surface scratches, and/or inaudible or barely audible scuffs. a very nice used record
VG+ : no groove wear, but some visible scuffs and surface scratches. Should still play with nice fidelity, but will have an occasional pop, tick, and light surface noise, surface noise between tracks. A normal used record.
VG : still showing good gloss but lots of small scratches and scuffs. A slightly abused record that should still play through without skips, but will have light surface noise throughout, pops, ticks, and maybe some light distortion around the edges. I do not consider VG to be a junk grade
VG- to G : any record in less than VG condition that I feel is still worth offering
M : perfect. no wear, square flat corners, solid seams, spine etc.
M-/NM : overall appearance of front and back near perfect but may have a very small problem or faint age wear that I will explain.
EX : as above, nice "un-handled" feel, but may have a small split, a bent corner or two, very light ring wear, small writing. Or a M- jacket with a drill hole, saw-cut, or promo stamp.
VG+ : still have a nice overall appearance, but may have the following defects: seam splits, spine splits, small tears, ring wear, writing, small stains, etc. in various (not severe) degrees.
VG : defects as above in a greater degree, and possibly a "handled", or "worn" feel to the paper. possible neat tape repairs. will still look good when in a poly-bag.
G or G+ : getting ugly, but for some reason still worth offering.