With Jack poorly she appears? (4)
I believe the answer is:
jill
'she appears?' is the definition.
I can't judge whether this defines the answer.
'with jack poorly' is the wordplay.
'with' says to put letters next to each other.
'jack' becomes 'j' (playing card abbreviation).
'poorly' becomes 'ill' ('ill' can be a synonym of 'poorly').
'j' put next to 'ill' is 'JILL'.
(Other definitions for jill that I've seen before include "Jack's pet" , "Female ferret" , "Jack's nursery rhyme girl companion" .)