adverb
as ... as possible
Bound adverbial form used almost exclusively in the set phrase 可及的速やかに (as soon as possible). Not freely productive in modern Japanese.
See also: 可及的速やかに
可及的速やかにご返信ください。
Please reply as soon as possible.
Compound of 可及 (possible, attainable) + 的 (adjectival suffix). The exact historical derivation is uncertain; the form is now fossilized in the phrase 可及的速やかに.