In a modern novel an angry father accuses his teenager son of doing nothing but dilly-dallying all over the town.
(dilly-dallying — wasting time, doing nothing, loitering)
Another example of a word made by reduplication may be found in the following quotation from The Importance of Being Earnest by O. Wilde:
Lady Bracknell. I think it is high time that Mr. Bunbury made up his mind whether he was going to live or to die. This shilly-shallying with the question is absurd.
(shilly-shallying — irresolution, indecision)
The earliest examples of this type of word-building are the verb to beg that was made from the French borrowing beggar, to burgle from burglar, to cobble from cobbler. In all these cases the verb was made from the noun by subtracting what was mistakenly associated with the English suffix -er. The pattern of the type to work — worker was firmly established in the subconscious of English-speaking people at the time when these formations appeared, and it was taken for granted that any noun denoting profession or occupation is certain to have a corresponding verb of the same root. So, in the case of the verbs to beg, to burgle, to cobble the process was reversed: instead of a noun made from a verb by affixation (as in painter from to paint), a verb was produced from a noun by subtraction. That is why this type of word-building received the name of back-formation or reversion.
Later examples of back-formation are to butle from butler, to baby-sit from baby-sitter, to force-land from forced landing, to blood-transfuse from blood-transfuing sorry