From The Collaborative International Dictionary of English v.0.48 [gcide]:
Triumphant \Tri*um"phant\, a. [L. triumphans, p. pr. of
triumphare: cf. F. triomphant. See Triumph, v. i.]
[1913 Webster]
1. Rejoicing for victory; triumphing; exultant.
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Successful beyond hope to lead ye forth
Triumphant out of this infernal pit. --Milton.
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2. Celebrating victory; expressive of joy for success; as, a
triumphant song or ode.
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3. Graced with conquest; victorious.
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Athena, war's triumphant maid. --Pope.
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So shall it be in the church triumphant. --Perkins.
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4. Of or pertaining to triumph; triumphal. [Obs.]
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Captives bound to a triumphant car. --Shak.
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Church triumphant, the church in heaven, enjoying a state
of triumph, her warfare with evil being over; --
distinguished from church militant. See under
Militant.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
triumphant
adj 1: joyful and proud especially because of triumph or
success; "rejoicing crowds filled the streets on VJ Day";
"a triumphal success"; "a triumphant shout" [syn:
exultant, exulting, jubilant, prideful,
rejoicing, triumphal, triumphant]
2: experiencing triumph [syn: triumphant, victorious]