French word soutien comes from Latin teneo, Latin subteneo, Latin sub- (Sub-.)

Detailed word origin of soutien

Dictionary entry	Language	Definition
teneo	Latin (lat)	(of laws) I am binding on; bind, hold, obligate. (reflexive) I keep back, remain, stay, hold position. I comprise, contain, include, hold. I hold fast, restrain, detain, check, control; bind, fetter. I hold, have; grasp. I insist, uphold. I know, grasp, understand, conceive. I possess, occupy, control. I reach, attain; gain, acquire, obtain. I recollect, retain knowledge of, remember, bear [...]
subteneo	Latin (lat)
sub-	Latin (lat)	Sub-.
sustineo	Latin (lat)	I hold or keep back or in, stay, check, restrain, control.. I hold up or upright, uphold, keep up, bear up, support, sustain, tolerate.. I keep back, put off, defer, delay.. I undergo, endure, deign, withstand, hold out.. I uphold, sustain, maintain, preserve; guard, protect.
*sustenīre	Vulgar Latin (la-vul)
sustenir	Old French (fro)	(by extension) to support; to sustain. To hold up; to support.
soustenir	Middle French (frm)	To keep up; to sustain.
soutenir	French (fra)	(used with que) to maintain (that). To keep up. To support.
soutien	French (fra)	Support (physical). Support (psychological/emotional).

Words with the same origin as soutien