Vet initially took fever to be unidentified (5)
I believe the answer is:
vague
'unidentified' is the definition.
Both the answer and definition are adjectives. Perhaps there's an association between them I don't understand?
'vet initially took fever' is the wordplay.
'initially' says to take the initial letters.
'took' means one lot of letters go next to another.
'fever' becomes 'ague' (I've seen this before).
The first letter of 'vet' is 'v'.
'v'+'ague'='VAGUE'
'to be' is the link.
Can you help me to learn more?
(Other definitions for vague that I've seen before include "Blurred" , "Indeterminate" , "Indistinct or not clearly expressed" , "Unclearly defined" , "Hazy" .)