An approximant, as a type of consonant, is rather difficult to describe; informally, we can say that it is an articulation in which the articulators approach each other but do no get sufficiently close to each other to produce a "complete" consonant such as a plosive, nasal or fricative. The difficulty with this is that articulators are always in some positional relationship with each other, and any vowel articulation could also be classed as an approximant -but the term "approximant" is usually used only for consonants.