In the discussion on full reduplication phenomenon in Korean, full reduplication is defined as operation to form word, and the case where stem or root is full reduplication is mainly discussed. In practice, however, it is not uncommon to find that the combination of verb and ending, or the combination of noun and particle, is reduplicated. They are distinguished from general syntactic expressions in that they can not interpret the meaning of the whole by the meaning of the constituents and are phonologically independent. In this paper, we propose that full reduplication can be applied to syntactic units such as the combination of verb and ending, and the combination of noun and particle based on construction grammar. On the other hand, the meaning expressed through full reduplication in Korean is mainly ‘plural, repetition, emphasis’. In this paper, we show that they can be systematically explained in terms of iconicity and semantic extension. The meaning of ‘plural’ and ‘repetition’ seems to be formed based on iconicity in the process of referring to various objects and situations. And the meaning of ‘emphasis’ can be seen as being extended from this.