Sharkish is an adjective that describes someone who behaves like a shark, which is seen as aggressive and predatory. However, if you are looking for different synonyms to convey the same meaning, there are several options to choose from. One possibility is to use the word predatory, which also implies someone who is hunting or preying on something. Another synonym for sharkish could be ruthless, which suggests that someone is without mercy or compassion. Similarly, ferocious can also work, which refers to someone who is savagely violent or fierce. Other options include cutthroat, brutal, and relentless, all of which capture the idea of someone who is aggressive and unyielding in their pursuits.