Close synonyms include dwell on. Each sense on this page lists its own synonyms, because a word with several meanings rarely has one substitute that works for all of them.
Is linger over a common word?
linger over is banded "Rare" — specialist or archaic — most readers will not have met it. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.
Definitions, synonyms and semantic relations for linger over come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. .