From Longman Dictionary of Contemporary Englishinexactin‧ex‧act /ˌɪnɪɡˈzækt◂/ adjective EXACTnot exact Earthquake prediction is an inexact science.
Examples from the Corpus
inexact• the inexact science of earthquake predictioninexact science• Entertaining, for sure, but an inexact science.• Some of them were really interested in meteorology, others only tolerant of what they considered to be a very inexact science.• That is why valuation, under the old rating system, was a most inexact science. 