electrofuge

https://doi.org/10.1351/goldbook.E01965
A leaving group that does not carry away the bonding electron pair. For example, in the nitration of benzene by $\ce{NO2^{+}}$, $\ce{H^{+}}$ is the electrofuge. The adjective of electrofuge is electrofugal.
Source:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1109 [Terms] [Paper]