getting caught up in; being dragged into; involvement; entanglement
Often used when someone becomes involved in trouble or an incident against their will, especially as collateral damage. Common in phrases like 巻き添えを食う (to suffer as a result of being dragged in).
See also: 巻き添え
He got caught up in his friend's crime.
I was injured as a result of being involved in the accident.
Standard spelling.
Variant spelling without okurigana き.
Compound of 巻き (maki, 'rolling' or 'winding') + 添い (zoi, 'accompanying'). The image is of being rolled up together with something else, hence getting inadvertently involved.