How far will five letters get you in extremity? (3)

I believe the answer is:

toe

I'm a little stuck... Click here to teach me more about this clue!

'extremity?' is the definition.
(I know that toe is a type of extremity)

I don't understand how the rest of the clue works.

(Other definitions for toe that I've seen before include "End of foot" , "End of sock" , "Calabria?" , "Digit; kick" , "Feature of footwear" .)

I've seen this clue in The Independent.

Want a hint initially instead of a full solution? Install my app