Question

When he said I wasn't there, I told him I was, and my buddy backed me up.‎

Accepted Answer

(idiomatichttps://en.wiktionary.org/wiki/Appendix:Glossary#idiomatic, transitivehttps://en.wiktionary.org/wiki/Appendix:Glossary#transitive) To provide support or the promise of support.

Sentence	When he said I wasn't there, I told him I was, and my buddy backed me up.‎
Definition	( idiomatic https://en.wiktionary.org/wiki/Appendix:Glossary#idiomatic , transitive https://en.wiktionary.org/wiki/Appendix:Glossary#transitive ) To provide support or the promise of support.

I Told Buddy Backed Up.‎ Provide Support Promise