Building laboratory's extremities in a playful way (6)
I believe the answer is:
archly
'in a playful way' is the definition.
I can't judge whether this defines the answer.
'building laboratory's extremities' is the wordplay.
'building' becomes 'arch'.
'laboratory's extremities' becomes 'ly' (I am not sure about this - if you are sure you should believe this answer much more).
'arch'+'ly'='ARCHLY'
Can you help me to learn more?
(Other definitions for archly that I've seen before include "In roguish manner" , "In a sly way" , "In a sly manner" .)