Choose fancy iron, finally metric, using computer control (10)
I believe the answer is:
electronic
'using computer control' is the definition.
(controlled by computers)
'choose fancy iron finally metric' is the wordplay.
'choose' becomes 'elect' (electing is a kind of choosing).
'fancy' indicates an anagram.
'finally' says to take the final letters.
The final letter of 'metric' is 'c'.
'iron' anagrammed gives 'roni'.
'elect'+'roni'+'c'='ELECTRONIC'
(Other definitions for electronic that I've seen before include "Like a computer" , "of some modern technology" , "Like a PC" , "of PC devices?" , "Using microchips, transistors, etc" .)