Ill at ease with writing in The Outsider (8)
I believe the answer is:
stranger
'the outsider' is the definition.
(I've seen this before)
'ill at ease with writing' is the wordplay.
'ill at ease' becomes 'strange' (synonyms).
'with' means one lot of letters go next to another.
'writing' becomes 'r' (one of the traditional three R's of education).
'strange'+'r'='STRANGER'
'in' acts as a link.
(Other definitions for stranger that I've seen before include "'Weirder, odder (8)'" , "Outsider" , "Person in place or company to which he does not belong" , "More curious or unfamiliar" , "unfamiliar figure" .)