lags

verb

Falls behind others; moves or develops more slowly than expected.

"The runner lags behind the leader."

noun

British slang for prisoners or convicts, especially those serving long sentences.

"The old lags shared stories in the prison yard."

Thesaurus

Synonyms: fall behind, fall back, dawdle, jug, immure, gaol, put behind bars, incarcerate, imprison, remand, put away, jail