While some lexical errors are due to improper dictionary use, others result from learners' attempts to apply the patterns they know in order to filí lexical gaps. The extent to which these attempts reflect acquisition of L2 derivational morphology, as opposed to transfer from Li, has been subject to debate. This paper summarizes an analysis of errors from non-native writers of Spanish enrolled in an upper-division course, showing that these students are indeed beginning to apply Spanish word-formation rules. Nevertheless, their neologisms still seem to be partially guided by Li counterparts, and they ofien resort to an alternative: semantic extension of existing vocabulary. The inconsistency of strategies points to an overalí principle of what 1 have termed "Making-Do": when learners encounter a lexical gap and cannot resort to a dictionary, they take a Spanish (or quasi-Spanish) term, adapt it however seems best, and make it do for the new meaning or function.