adjective
smooth, slippery
B1
Glatt means 'smooth' or 'slippery'. It's gradable: comparative glatter, superlative am glattesten. Antonym rau. Used for surfaces (smooth) or conditions (slippery). As an adjective it agrees with noun gender/case. Not a participle. Can be used figuratively: 'glatt gelaufen' meaning something went smoothly.
Examples
Die Straße war glatt, sodass mehrere Autos ins Schleudern gerieten, obwohl die Stadt zuvor gestreut hatte.
The road was slippery so that several cars skidded, although the city had salted it earlier.
Nach dem Regen ist der Gehweg glatt.
After the rain the pavement is slippery.
Die Fläche des Tisches ist glatt.
The surface of the table is smooth.
Details
Mnemonics
Picture a glossy, glass-like surface with no bumps — completely smooth.
Sounds a bit like English 'glad' — imagine being smooth and pleased.
Notes
Common adjective with several senses: 'smooth' (surface), 'slippery' (dangerous underfoot), and colloquially 'completely' as in 'glatt gelogen' (outrightly lied).