köken: Univerbation of en bon point (“in good condition”). The rule in French is to write ⟨m⟩ instead of ⟨n⟩ before ⟨m⟩, ⟨p⟩ or ⟨b⟩ – here the rule is applied to the first ⟨n⟩ but not the second, since it does not apply to words derived from bon; compare bonbon, bonbonnerie, bonbonnier and bonbonnière. The word bonbonne, however, is not derived from bon, but from Occitan boumbouno, ultimately from Latin…
Quoique La Brière fût alors mince, il appartient à ce genre de tempéraments qui, formés tard, prennent à trente ans un embonpoint inattendu.