thin as a rake
thin as a rail
overthin
thin as a wafer
skinny
bony
boney
weedy
scrawny
underweight
scraggy
scraggly
slim jim
wafer-thin
skinny-malinky
waif
skeleton
superthin
thin as a yard of pump water
ultrathin
scratty
thinliness
femmer
hairline
thinny
exility
slim
slender
bare-boned
ultraslim
skinnily
superslim
thin
scrag
thin person
skin and bones
all skin and bones
Biafran
superskinny
lithe
slender-bodied
lean
spare
thin-bodied
slim-bodied
emaciate
tenuity
trim
anorexic
slimness
slenderness
slightness
slimly
penurious
semithin
macilent
look as if one has been dragged through a hedge backwards
skin-deep
wasp-waisted
breath and britches
straight
araneous
thinness
scrawniness
microthin
ill-groomed
wisplike
thinnish
blobbily
gaunt
scrawnily
slimily
thinner
haggard
extenuated
skinnyish
cadaverous
emaciated
skeletal
pinched
wasted
wispy
tenuous
razor-thin
scranky
skinniness
meager
meagre
slink