Clingy type is flaccid and extremely expectant (6)
I believe the answer is:
limpet
'clingy type' is the definition.
(I've seen this before)
'flaccid and extremely expectant' is the wordplay.
'flaccid' becomes 'limp' (synonyms).
'and' means one lot of letters go next to another.
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'expectant' with its centre removed is 'et'.
'limp'+'et'='LIMPET'
'is' is the link.
(Other definitions for limpet that I've seen before include "Shellfish that sticks to surface" , "It clings to rock surfaces" , "Marine mollusc" , "Rock lover" , "Cinging mollusc" .)