Malaysian in Borneo, extremely doughty and keen at first (4)
I believe the answer is:
dyak
'malaysian in borneo' is the definition.
The definition suggests a singular noun which matches the answer.
'extremely doughty and keen at first' is the wordplay.
'extremely' means to remove the middle letters (only the extremes of the word are used).
'at first' says to take the initial letters.
'doughty' with its middle taken out is 'dy'.
The initial letters of 'and keen' is 'ak'.
'dy'+'ak'='DYAK'
Can you help me to learn more?
(Other definitions for dyak that I've seen before include "Long-house dweller" , "Tribesman" , "far Eastern dialect" , "Language of Borneo" .)