Vocabulary researchers generally point out three strategies that learners apply in order to find out the meanings of unknown words on their own (Graves, 2006; 2007). The use of context, word parts, reference materials ((e.g. dictionaries, glossaries, thesauruses, both print and online) in-text definition/explanations, synonyms, examples, antonyms/contrasts, analogy have been added to these three ways (Gu and Johnson, 1996). The meaning of an idiom can be predicted by cashing in on world knowledge of the reader as it is not randomly constructed or an arbitrary assignment. In the depth of many idioms may lie a metaphor or an assumption, for example, to predict the meaning of an idiom like "the ball is in your court" may prerequisite the assumption that we play a game or the metaphor that life is a game. In the same way, one may find the meaning quite transparent if s/he has some encyclopedic assumptions about the type of activity, sport or game which the expression alludes to, and the ability to derive implications using these assumptions. Taking the predictability of the meaning of an idiom as idiom transparency, readers may also infer the meaning of an idiom by establishing relevance with their background experience and knowledge (Moreno, 2017). Taking all above into account, the present paper has a two-fold aim: It first aims to unveil vocabulary engagement strategies of L2 students in decoding word meaning in general at tertiary level in a state university in Turkey. Secondly, the way how the meanings of idioms are determined in the text is explored as the conflict between literal meaning and idiomatic expressions emerges as one of the challenges before the learners of foreign languages. With this aim, an already-prepared literature-based list of strategies were presented to the participants who are all college students after they were delivered the texts with unfamiliar vocabulary. Unfamiliar vocabulary also contained idioms that are transparent and opaque in meaning. The list contained strategies such as surrounding language cues, word parts, contextual cues, compositional meaning of the words, idiom-inherent features, and relevance to background knowledge and experience. The participants were also asked to describe their own way of deciphering unfamiliar word. It is expected that such an exploration of vocabulary engagement strategies will contribute to teaching vocabulary in foreign/second language teaching. [Paper presented at the GLOBELT2018 Conference in Belgrade, Serbia in May 10-13, 2018.]