No daughter glides in Utah - it's most hideous! (7)
I believe the answer is:
ugliest
'most hideous' is the definition.
('ugly' can be similar in meaning to 'hideous')
'no daughter glides in utah' is the wordplay.
'no' indicates named letters should be taken away.
'daughter' becomes 'd' (genealogical abbreviation).
'in' means one lot of letters goes inside another.
'utah' becomes 'UT' (abbreviation).
'glides' with 'd' removed is 'glies'.
'glies' inserted inside 'ut' is 'UGLIEST'.
'it's' is the link.
(Other definitions for ugliest that I've seen before include "Least attractive" , "Least pretty" , "superlatively unattractive" , "Most deficient in beauty" , "Least beautiful" .)