Believing something because you want it to be true, not because it is realistic.
現実的ではなく、そうであってほしいから何かを信じること。 (Genjitsuteki de wa naku, sou de atte hoshii kara nanika o shinjiru koto)
"Believing you'll win the lottery is just wishful thinking."
"宝くじに当たると思うのは、ただのウィッシュフル シンキングです。" (Takarakuji ni ataru to omou no wa, tada no wishful thinking desu)
in a safe or stable situation
To pursue a mistaken or misguided course of action.
to be so worried or stressed that you don’t know what to do
to work hard and continuously
a useless or hopeless pursuit
to buy something at a low price; to make a bargain