Expectation, Prediction
noun, verbal noun, の adjective
If you consider the future beforehand and imagine how things will turn out (based on some facts), you will have an informed expectation or prediction for it. 予想 refers to an expectation or prediction about the future based on current information or trends, like predicting which candidate will win an upcoming election or estimating future economic conditions.
よそう
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
私は未来が予想できるんです。
I can predict the future.
私の予想は見事に外れてしまいました。
My prediction turned out to be completely wrong.
それは予想外でした。
That was unexpected.