thus, so, like, such
偌 centers on indicating manner or similarity: 'thus', 'so', 'like', or 'such'. It is a rare character used to point to a way of being or doing.
偌 is a phono-semantic compound: 亻 (person) suggests a human-related concept, and 若 provides the sound. The exact historical development is uncertain, and the character is rare in Japanese.
A person 亻 beside 若 (which can mean 'young' or 'like'): imagine someone acting 'like' or 'such' a way, pointing to a manner.
For ジャ, picture a person saying 'just like that' with a sharp 'ja!' sound: 'ja' cues ジャ, and the person 亻 points to the manner.