This contribution addresses the general theme of Multifunctionality and syncretism in non-finite forms. When we see a particular form in a number of different environments yielding different effects, what does it mean to say that this reflects multifunctionality rather than syncretism? As a refinement of multifunctionality the notion of ‘multi-effectuality’ is introduced: one element participates in different derivations, performing one and the same operation, but yields different interpretive effects depending on the environment. The analysis takes as a starting point the role of the affix -en in Dutch. The canonical view is that when attached to a verb stem, -en functions either as an infinitival marker or as a nominalizing affix. It is shown that this view cannot be maintained. The “functions” of -en are unified by analyzing it as projecting an ‘eventuality expression’, with different effects depending on the syntactic environment. The analysis is extended to English, focusing on the contrasts between Dutch and English infinitives and on the role of the English -ing affix in gerunds and participles. The discussion proceeds with an analysis of Frisian with its two forms of the infinitive and concludes with some reflections on the relation between syntactic and semantic categories.