subtile (?.)
- Byzantine
- Machiavellian
- Machiavellic
- acute
- adulterated
- air-built
- airy
- arch
- artful
- astute
- attenuate
- attenuated
- cagey
- calculating
- canny
- chimerical
- clever
- cloud-built
- crafty
- cunning
- cut
- cute
- dainty
- deceitful
- deep
- deep-laid
- delicate
- designing
- devious
- dilute
- diluted
- diplomatic
- dreamlike
- ethereal
- fanciful
- fatuitous
- fatuous
- feline
- fine
- flimsy
- foxy
- gaseous
- gossamery
- guileful
- illusory
- imaginary
- ingenious
- insidious
- insubstantial
- inventive
- knowing
- pawky
- phantomlike
- politic
- rare
- rarefied
- ready
- resourceful
- scheming
- serpentine
- shadowy
- sharp
- shifty
- shrewd
- slick
- slight
- slippery
- sly
- smooth
- snaky
- sneaky
- sophistical
- spirituous
- stealthy
- strategic
- subtle
- supple
- tactical
- tenuous
- thin
- thinned
- thinned-out
- trickish
- tricksy
- tricky
- uncompact
- uncompressed
- unreal
- unsubstantial
- vaporous
- vulpine
- wary
- watered
- watered-down
- wily
- windy