What does Eren mean by tatakae?

Tatakae can be translated as: Go to fight; Fight! Go to battle! Strength!

Who is tatakae in AOT?

‘Tatakae’ basically means ‘to fight’. In season 4 Eren says ‘Tatakae’ to keep himself motivated and to keep moving forward despite the harsh steps he’s about to take like calling Mikasa a ‘slave’ and telling her that he hates her, fighting Armin, acting like the goddam villain. He had to do it to keep himself going.