Shake head finally facing stranger (6)
I believe the answer is:
dodder
'shake' is the definition.
(thesaurus)
'head finally facing stranger' is the wordplay.
'finally' indicates one should take the final letters.
'facing' means one lot of letters go next to another.
'stranger' becomes 'odder' (I've seen this before).
The final letter of 'head' is 'd'.
'd'+'odder'='DODDER'
(Other definitions for dodder that I've seen before include "Totter into the Dublin river" , "Be slow and unsteady" , "Hesitate" , "go falteringly" , "Walk unsteadily along the Dublin river?" .)