What did Guy say in his fight vs Madara?
Around 1:24 of your clip, Guy says 「積」 seki. This is not really a word, per se, but you can take it to "mean" something like "to accumulate" - it is the same character used in the verb 積もる tsumoru, which means just that. 

Then, at 4:14, the thing he says is 「流」 ryuu. Again, this is also not really a word, but it is the same character used in 流れる nagareru, which means "to flow". 

According to some random blog I found, Guy apparently says the former utterance to build up chakra, and then the latter utterance to release that same chakra. You probably didn't notice, given the prolonged flashback in between the two utterances.