割込む
わりこむ · warikomu · JLPT N1 · verb-godan
to cut in
✂️ 割込む = 割る (split) + 込む (push into): split the crowd and push in
割 means split or break, and 込む means crowd into. Together they describe forcing your way into a gap in a line or a conversation, which is cutting in.
割 — 害 (harm, phonetic) + 刂 (knife radical)
A semantic-phonetic compound: the knife radical 刂 gives the meaning 'cut,' while 害 supplies the sound. The original sense was to cut or slice with a blade, which extended to 'divide' and 'allot a share.' Modern uses like 割爱 (give up something dear) preserve this idea of cutting away.