"Indubitably". It means, "without a doubt". Not only is it the best and most incredible word EVER created in the English language, it is also very fun to say! Indubitably, Indubitably, Indubitably! Doesn't it make you smile?!
It is also fun to use that word in response to a text message instead of other adjectives. If you want to go for even more pizazz, try adding in a British accent and then using it. Funny, huh?
Here's the prim and proper definition: Merriam Webster
Now here's my favorite online dictionary's definition: Urban Dictionary
Now, don't you feel smart? The best part is that you now have a fun, new word to use! Instead of using a simple "yes" to agree with someone today, use the term "indubitably", and say it with a straight face while the other person around you laughs!