This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 劜 is uncertain. It visually combines 力 and 乚, but the original semantic or phonetic role of these components is unclear.
With no clear meaning, picture a strong person (力) bending something (乚) with force, but the result is unknown.
For アツ, imagine the strong person pressing down with an 'ats!' of effort: ats -> アツ, as they bend the object.