Prediction house mostly went up, get by (9)
I believe the answer is:
horoscope
'prediction' is the definition.
(horoscope is a kind of prediction)
'house mostly went up get by' is the wordplay.
'house' becomes 'ho' (abbreviation for house).
'mostly' means to remove the last letter (most but not all of the word).
'went up' becomes 'rose' (I've seen this in another clue).
'get by' becomes 'cope' (synonyms).
'rose' with its last letter taken away is 'ros'.
'ho'+'ros'+'cope'='HOROSCOPE'
(Other definitions for horoscope that I've seen before include "An astrological forecast" , "special map" , "Forecast of fortune" , "Astrologer's prediction" , "Forecast of a person's future based on the heavens" .)