Will 100% whey make my arms bigger and make them look defined? i lift dumbbell weights 3

No.
Making muscles bigger and more defined there's 2 different stragegies and
usually you can't do both at the same time. First gain mass, drink weight gainer
2 or more times a day to gain the weight you want while lifting heavy heavy
weights to build muscle. After that you can switch to just whey protein while
you're cutting fat. Really can't do both at the same time though.
No