The word "fixt in mind" is an archaic spelling of "fixed in mind" which means to be firmly decided or determined. The spelling of "fixt" uses an archaic form of the suffix "-ed" which was commonly used in Middle English. The IPA phonetic transcription for "fixt" would be /fɪkst/ with the "x" pronounced as /ks/. Overall, the word "fixt" may be considered an obsolete spelling now, but it remains an interesting aspect of the evolution of the English language.