Those incisive ones at the front? (5)
I believe the answer is:
teeth
'front?' is the definition.
Although both the answer and definition are verbs in their base form, I cannot understand how they can define each other.
'those incisive ones at the' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'the' is 'eth' which is present in the answer.
The remaining letters 'te' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for teeth that I've seen before include "Gearwheel projections" , "Feature of an effective bill" , "Cog wheel projections" , "Dentures" , "The most violent" .)