The definition of hanker is to long for something.(verb)
Wanting chocolate desperately is an example of hanker.
See hanker in Webster's New World College Dictionary
Origin: Early ModE, prob. < Du or LowG source, as in Fl hankeren, to desire, long for, Du hunkeren, freq. formation & metaphoric extension < base of hang
See hanker in American Heritage Dictionary 4
intransitive verb han·kered, han·ker·ing, han·kers
Origin: Perhaps from Dutch dialectal hankeren; see konk- in Indo-European roots.
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