dwin·dle 
(dwĭndl)
(dwĭndl)v. dwin·dled, dwin·dling, dwin·dles
v.intr.
To become gradually less until little remains. See Synonyms at decrease.
v.tr.
To cause to dwindle: difficulties that dwindled my enthusiasm for the recipe.
[Frequentative of Middle English dwinen, to waste away, from Old English dwīnan, to shrink; see dheu-2 in the Appendix of Indo-European roots.]