The Collaborative International Dictionary of English v.0.48:
Neat \Neat\, a. [Compar. Neater; superl. Neatest.] [OE.
nett, F. nett, fr. L. nitidus, fr. nitere to shine. Cf.
Nitid, Net, a., Natty.]
1. Free from that which soils, defiles, or disorders; clean;
If you were to see her, you would wonder what poor
body it was that was so surprisingly neat and clean.
2. Free from what is unbecoming, inappropriate, or tawdry;
simple and becoming; pleasing with simplicity; tasteful;
chaste; as, a neat style; a neat dress.
3. Free from admixture or adulteration; good of its kind; as,
neat brandy; to drink one's vodka neat. Hence: (Chem.)
Pure; undiluted; as, dissolved in neat acetone. "Our old
wine neat." --Chapman.
[1913 Webster +PJC]
4. Excellent in character, skill, or performance, etc.; nice;
finished; adroit; as, a neat design; a neat thief.
5. With all deductions or allowances made; net.
Note: [In this sense usually written net. See Net, a.,
neat line (Civil Engin.), a line to which work is to be
built or formed.
Neat work, work built or formed to neat lines.
Syn: Nice; pure; cleanly; tidy; trim; spruce.