Massage European, entering clammy all over (5)
I believe the answer is:
knead
'massage' is the definition.
(I know that massage can be written as knead)
'european entering clammy all over' is the wordplay.
'european' becomes 'E' (abbreviation e.g. EU).
'entering' indicates putting letters inside.
'clammy' becomes 'dank' (synonyms).
'all over' is a reversal indicator.
'e' inserted inside 'dank' is 'daenk'.
'daenk' written backwards gives 'KNEAD'.
(Other definitions for knead that I've seen before include "Work (dough) into mass" , "Somehow work in" , "Manipulate" , "Work dough or massage flesh" , "Work (dough/clay)" .)