Stranger with additional lager possibly losing head (6)
I believe the answer is:
eerier
'stranger' is the definition.
(eerie means odd or strange)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for eerier that I've seen before include "More strangely frightening" , "Stranger" , "More uncanny" , "More strange and frightening" , "More weird" .)