beetle vs beetling

beetle is a noun but beetling is not a noun.

Word	Noun	Adjective	Verb	Adverb
beetle	Yes	Yes	Yes	No
beetling	No	Yes	No	No

As adjectives, beetle and beetling are synonyms defined as:

beetle (noun)	beetling (noun)
insect having biting mouthparts and front wings modified to form horny covers overlying the membranous rear wings
a tool resembling a hammer but with a large head (usually wooden); used to drive wedges or ram down paving stones or for crushing or beating or flattening or smoothing

beetle (adjective)	beetling (adjective)
jutting or overhanging	jutting or overhanging

beetle (verb)	beetling (verb)
beat with a beetle
fly or go in a manner resembling a beetle
be suspended over or hang over