penance / pennants are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
penance: (noun) a Catholic sacrament; repentance and confession and atonement and absolution. (noun) voluntary self-punishment in order to atone for some wrongdoing.
pennants: (noun) the award given to the champion. (noun) a flag longer than it is wide (and often tapering). (noun) a long flag; often tapering.
penance: p·EH·n·ah·n·s
pennants: p·EH·n·ah·n·t·s
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)