To be gainful means to be profitable, advantageous, or fruitful. There are several synonyms for the word that convey similar meanings but vary in tone and usage. For instance, the word lucrative describes something that is highly profitable or yielding a lot of money. Another synonym is advantageous, which suggests that something is beneficial and helpful in achieving a desired outcome. Similarly, fruitful implies that something is productive and abundant in yielding positive results. Other synonyms for gainful include beneficial, remunerative, profitable, and rewarding. All these words can be used to describe situations, investments, or business ventures that are profitable or beneficial in some way.