Meaning:

• These or this
• This one, this person, this thing
• They or he or she or it

Demonstrative pronoun.

οὗτος usually refers to something close to the speaker — “this” as opposed to ἐκεῖνος (“that”).

• οὗτος → “this one right here”
• ἐκεῖνος → “that one over there”

It can refer to:

• What is near physically: οὗτος ὁ ἄνθρωπος — “this man” (John 9:16plugin-autotooltip__default plugin-autotooltip_bigJohn 9:16
  
  Greek ἔλεγον οὖν ἐκ τῶν Φαρισαίων τινές· οὐκ ἔστιν οὗτος παρὰ θεοῦ ὁ ἄνθρωπος, ὅτι τὸ σάββατον οὐ τηρεῖ. ἄλλοι ἔλεγον· πῶς δύναται ἄνθρωπος ἁμαρτωλὸς τοιαῦτα σημεῖα ποιεῖν; καὶ σχίσμα ἦν ἐν αὐτοῖς. ESV Some of the Pharisees said, “This man is not from God, for he does not keep the Sabbath.” But others said, “How can a man who is a sinner do such signs?” And there was a division among them.…)
• What was just mentioned: καὶ τοῦτο ἐστίν… — “and this is…” (1 John 5:11plugin-autotooltip__default plugin-autotooltip_big1 John 5:11
  
  Greek καὶ αὕτη ἐστὶν ἡ μαρτυρία, ὅτι ζωὴν αἰώνιον ἔδωκεν ἡμῖν ὁ θεός, καὶ αὕτη ἡ ζωὴ ἐν τῷ υἱῷ αὐτοῦ ἐστιν. ESV And this is the testimony, that God gave us eternal life, and this life is in his Son. NIV And this is the testimony: God has given us eternal life, and this life is in his Son. NLT And this is what God has testified: He has given us eternal life, and this life is in his Son.…)
• What is about to be mentioned: τοῦτο λέγω… — “this I say…” (1 Corinthians 15:50plugin-autotooltip__default plugin-autotooltip_big1 Corinthians 15:50
  
  Greek Τοῦτο δέ φημι, ἀδελφοί, ὅτι σὰρξ καὶ αἷμα βασιλείαν θεοῦ κληρονομῆσαι οὐ δύναται, οὐδὲ ἡ φθορὰ τὴν ἀφθαρσίαν κληρονομεῖ. ESV I tell you this, brothers: flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable. NIV I declare to you, brothers, that flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable.…)

There are a number of idiomatic expressions that involve οὗτος:

• ἐν τούτῳ — “in this / by this” (very common in John’s letters), e.g. ἐν τούτῳ γινώσκομεν… — “By this we know…” (1 John 4:9plugin-autotooltip__default plugin-autotooltip_big1 John 4:9
  
  Greek ἐν τούτῳ ἐφανερώθη ἡ ἀγάπη τοῦ θεοῦ ἐν ἡμῖν, ὅτι τὸν υἱὸν αὐτοῦ τὸν μονογενῆ ἀπέσταλκεν ὁ θεὸς εἰς τὸν κόσμον ἵνα ζήσωμεν δι’ αὐτοῦ. ESV In this the love of God was made manifest among us, that God sent his only Son into the world, so that we might live through him. NIV This is how God showed his love among us: He sent his one and only Son into the world that we might live through him.…)
• διὰ τοῦτο — “because of this / therefore”
• μετὰ ταῦτα — “after these things”, e.g. μετὰ ταῦτα ἦν ἑορτὴ τῶν Ἰουδαίων — “After these things there was a feast of the Jews” (John 5:1plugin-autotooltip__default plugin-autotooltip_bigJohn 5:1
  
  Greek Μετὰ ταῦτα ἦν ἡ ἑορτὴ τῶν Ἰουδαίων, καὶ ἀνέβη Ἰησοῦς εἰς Ἱεροσόλυμα. ESV After this there was a feast of the Jews, and Jesus went up to Jerusalem. NIV Some time later, Jesus went up to Jerusalem for a feast of the Jews. NLT Afterward Jesus returned to Jerusalem for one of the Jewish holy days.)