Description from the designer:
Optimo! is a fast-paced word game in which you have to be the quickest to find the best word with each round's setting.
In each round, you have a combination of six cards with constraints (letter or lexical). These constraints can be a requirement (i.e. you must use the letter "E" or you must have six letters in the word) or a ban (i.e. you can't use verbs or you can't have a word with 4 or less letters).
Then you must find a word that corresponds to at least 4 constraints, then trigger the timer to give the other players 30 seconds more to find a better word than yours. Pondering if you should find a 5(or 6)-constraint word or go fast with a 4-constraint word to get the fastest-player bonus but risk losing it all to a better word is the core mechanic of the game.