Neatest

adjective

1. Clean, tidy; free from dirt or impurities.

   "My room is neat because I tidied it this morning.  She has very neat hair."

2. Free from contaminants; unadulterated, undiluted. Particularly of liquor and cocktails; see usage below.

   "I like my whisky neat."

3. Conditions with a liquid reagent or gas performed with no standard solvent or cosolvent.

   "The Arbuzov reaction is performed by adding the bromide to the phosphite, neat.  The molecular beam was neat acetylene."

4. With all deductions or allowances made; net.
5. Having a simple elegance or style; clean, trim, tidy, tasteful.

   "The front room was neat and carefully arranged for the guests."