Monty broke into slangy, rapid French, gesticulating and hopping from foot to peg-leg and back again.
The letter is brimful of slangy vivid expressions.
The play was full of slangy dialogue.
a slangy expression; slangy speech.
with slang; in a slangy manner.
This slangy word is falling off from English.
Don't use such slangy expressions in your essays.