A small jug found in the wood (5)
I believe the answer is:
aspen
'wood' is the definition.
Both the definition and answer are adjectives. Maybe there's a link between them I don't understand?
'a small jug found in' is the wordplay.
'a' becomes 'an'.
'small' becomes 's' (abbreviation - e.g. clothes size).
'jug' becomes 'pe' (I am not sure about this - if you are sure you should believe this answer much more).
'found in' means one lot of letters goes inside another.
's'+'pe'='spe'
'an' going around 'spe' is 'ASPEN'.
'the' is the link.
Can you help me to learn more?
(Other definitions for aspen that I've seen before include "somewhere in Colorado" , "Trembler" , "Growth" , "Very timid" , "Tree, kind of poplar" .)