When an adjectival adverb modifies another adjective, the adjectival adverb is almost always used as an evaluative adjective. Consider the following contrast:

Apparently, the adjective's meaning consists of two parts, [HIGH DEGREE] and [WEIGHT]. In its adverbial function, the adjective has lost its literal meaning involving [WEIGHT], but it has retained its high degree meaning. As an adjective, swierheavy would be non-subjective, but in its adverbial use it became into an evaluative adjective, belonging to the same class as ferdomddamned and tigevery. These all involve a high degree reading. Hence, if the idiomatic restrictions on the collocation allow it, evaluative adverbs can regularly replace one another without significant change of meaning. So, alongside swier siikseriously ill, we may also have the following:

The evaluative adverb often forms an idiomatic collocation with the adjective which it modifies. For example, the evaluative adverb glûpendesneakingly is mainly used in combination with the adjective kâldcold. Some more idiomatic combinations are given in the table below, where the adverbs have lost their literal meaning, merely causing a high degree reading on the adjective which they modify:

stjerrende wierdyingly trueabsolutely true

stomme graachstupidly eagervery eagerly, very much

rare smoarchweirdly dirtyvery dirty

glêd ferkeardslipperly wrongvery wrong

From the list above it can be inferred that high degree adverbs end in schwa. In fact, some evaluative adjectives not ending in schwa may be marked with a schwa in case they are used as adverbs:

Most evaluative adverbs mark a high degree, but they can also mark a low degree. Consider the minimal pair below:

In the examples above, the adverbs have lost their literal meaning. An adjective or adverb causing a high degree reading is also referred to as an amplifier, and one causing a low degree reading is also referred to as a downtoner or a downtoning intensifier. However, loss of literal meaning is not due to the conversion to adverb in these cases, since they can also be used as high degree adjectives without being adverbial:

Anyway, there are also cases where the adverb marks a high degree while retaining its literal meaning. Consider the following examples: