Our gathering will be informal.
We can bring these issues up during an informal conversation with our staff
The organizer was late to our informal orientation.
A word used in an informal manner "The precedent said, 'What's up hommie' (to borrow the colloquialism)."
You don't need a fancy dress for an informal occasional.
You just did! Zilch is a slang word for zero, used only with very informal tone.
The dinner party was an informal affair held by a neighbor.Informal changes can be made to the Constitution by laws and interpretations of laws.
The word 'thru' is an informal spelling of the word 'through'.Example sentence: Read thru Chapter 8
"Specs" is an informal word for spectacles, although many people don't use the word at all, and use "glasses" instead.
(note: who'll is considered an informal use, a contraction of who will)With such a group of athletes, no one can predict who'll come in first.Who'll go to the store for me?
A good way to use retentive in a sentence is... "How do you use the word retentive in a sentence?"
use it by saying- how can you use the word ebullient in a sentence?
yes but it depends if you want your writing to be formal or informal.