Broadly speaking, a Zionist is someone who believes in the project of Jews re-settling their ancient national homeland from where the Romans expelled the vast majority of Jews nearly two thousand years ago. Zionists are either secular or religious. For the secular, the purpose of Israel is so the Jews can escape the discrimination, injustice, forced subservience, and outright murder they have so often experienced in other countries, so going home to be their own nation again is the best thing; for the religious, Canaan is the Promised Land that G-d took Jews out of Egypt for so Jews returning to it is an honor, maybe even an obligation - and for Christians a miracle and a sign that (perhaps) that G-d's Kingdom will come soon.
"i always thought zionist are more like aliens whom only radical muslim can see. "
I always thought that to a radical muslim everybody else was a "Zionist" and they couldn't see anything else.