Sort of reaction from the French in cooking garlic? (8)
I believe the answer is:
allergic
'sort of reaction' is the definition.
'the french in cooking garlic?' is the wordplay.
'the french' becomes 'le'.
'in' is an insertion indicator.
'cooking' indicates an anagram.
'garlic' anagrammed gives 'alrgic'.
'le' placed inside 'alrgic' is 'ALLERGIC'.
'from' acts as a link.
(Other definitions for allergic that I've seen before include "acting defensively" , "Reacting (med.)" , "Physically intolerant" , "Reacting badly to certain things" , "Having an adverse reaction (to something)" .)