びる

1. 1Of a person, to have the manner or appearance of a certain type of person, such as seeming grown-up or childish.Ex. 1
2. 2Of things or places, to take on a certain quality, such as looking old, worn, or rustic (古びる, 田舎びる).

It is used mainly in the forms 〜びている and 〜びた + noun to describe how someone or something appears, as in 大人びた顔 or 古びた建物. It describes an appearance or air that is naturally there rather than an intentional act, which sets it apart from ぶる. Unlike じみた, it is not inherently critical.

• めくN1「めく」 is a godan verb (「〜めいた」「〜めいている」) that typically attaches to season words and to words like 「謎」 and 「皮肉」, indicating that a season is showing signs or that speech, behavior, or atmosphere carries a certain nuance. The two rarely share collocations (you don't say 「春びる」); only a few, such as 「古めく」 and 「古びる」, can be used side by side.
• じみたN1「じみた」 attaches only to nouns but combines with more words than 「びる」, as in 「狂気じみた」 and 「芝居じみた」; it mostly carries a negative connotation and is neutral in register. With 「子供」 and 「大人」, the two are close in meaning.
• ぶるN1「ぶる」 means deliberately affecting an appearance or putting on airs, with a clearly negative connotation; it attaches to nouns and adjective stems, conjugates as a godan verb (「ぶった」), and is neutral in register. 「大人ぶる」 means pretending to be an adult and cannot be swapped with 「大人びる」.
• っぽいN3「びる」 is limited to a few fixed words like 「大人びる」 and leans literary, while 「っぽい」 attaches freely to nouns, adjective stems, and verb masu-stems, leans colloquial, and also has the senses 'prone to …' and 'having a strong tinge of …'. Only the 'seeming like …' sense is close between the two.
• げN2「げ」 forms na-adjectives, attaching to emotion adjectives and to forms such as 「たげ」 and 「ありげ」, and describes emotions or thoughts that show in a person's expression; 「びる」 forms an ichidan verb, is used only in a few fixed words, and describes people or things seeming like … or becoming old. The two are not interchangeable.
• がるN4「がる」 attaches to the stems of adjectives of emotion, sensation, or desire, or to 「たい」, and indicates a third person showing their inner feelings through words and behavior; 「びる」 is limited to a few fixed words, describes people or things looking like …, and leans literary. The two are not interchangeable.

びる describes a natural air of X, while ぶる means deliberately pretending to be X, じみた implies a disapproving 'smacking of X', and めく means 'showing signs or a hint of X'. っぽい is a casual, freely productive 'X-ish', げ marks an outward look of a feeling on adjective stems, and がる describes someone else showing a feeling or desire.