Maudlin knight hampered by desire to follow mum (7)
I believe the answer is:
mawkish
'maudlin' is the definition.
(synonyms)
'knight hampered by desire to follow mum' is the wordplay.
'knight' becomes 'k'.
'hampered by' is an insertion indicator.
'desire' becomes 'wish' (wish is a kind of desire).
'to follow' means one lot of letters go next to another.
'mum' becomes 'ma' (ma can mean mother).
'k' inserted within 'wish' is 'wkish'.
'wkish' put after 'ma' is 'MAWKISH'.
(Other definitions for mawkish that I've seen before include "Sentimental, schmaltzy" , "Cloying" , "Effusively or insincerely emotional" , "Falsely sentimental" , "Soppy" .)