No. They are just teachers but not Gurus as far as how Gurus are understood in Hindu Dharma.

In Vedic Dharma Guru is one who initiates you into the Vedas by giving you the Gayatri Mantra. This Samskara is called the sacred thread ceremony or the [Upanayanam][1].

> [![enter image description here][2]][2]
> 
> Manu Smriti 2.149. (The pupil) must know that that man also who
> benefits him by (instruction in) the Veda, be it little or much, is
> called in these (Institutes) his Guru, in consequence of that benefit
> (conferred by instruction in) the Veda.

And in Tantra Guru is one who relieves you from the ignorance by initiating you into a Mantra. This process is called the Guru Deeksha or the Mantra Deeksha. The Mantra is called the Guru Mantra.

In Tantra, there are three lines of Gurus : The Divine Line, The Enlightened Line, and the line of Human Gurus.

The Divine line or the Divyauga Guru Pangti consists of 12 Gods like Adi Natha and his consort, Sadashiva and his consort, Iswara and his consort, Rudra and his consort, Vishnu and his consort, etc.

The enlightened line of Gurus or the Siddhauga Pangti comprises of 11 Gurus viz-Sanaka, Sanananda, Sanatana, Sanatkumar, Sanat-Sujata, Dattatreya, Vyasa, Vamadeva etc.

And, the human line of Gurus or the Manavauga Pangti consists of 6 human beings viz : Nrisimha, Mahesha, Bhaskara, Mahendra, Madhava, and Vishnu (not to be confused with Lord Vishnu ).

And the disciples of these 6 human Gurus are all the Hindu Gurus in the current world.

> **Divyaughe** ChAdinAthashcha Tacchshaktischa sadAshivaha| Tathpatni Cheswarastasya BhAryA Rudrascha Tadvaduhu|| Vishnushcha TathpriyA
> BrahmA TathkanthA **DwAdaseritAha**|
> 
> The Divyauga Guru Pangti consists of 12 names- Adinatha, Sadashiva,
> Iswara, Rudra, Vishnu and Brahma along with their respective shaktis
> or consorts.
> 
> **Siddhaughe** Sanakaishchaba Sanandashcha SanaAtanah| SanatkumArascha SanathsujAtascha Rhibhukshajah|| DattAtreyo Raibtako VAmadevastathaha
> Parma| Tato VyAsah Sukaishchava **Ekadasha SamiritA**||
> 
> The enlightened Gurus are 11 in number and they are- Sanaka, Sananda,
> Sanatana, Sanathkumara, Sanath-Sujath, Rhibhukshaja, Dattatreya,
> Raivataka, Vamadeva & Vyasa.
> 
> **MAnvaughe** Nrisimhashcha Mahesho BhAskara TathA| Mahendro MAdhavo Vishnu **Shadethe Cha PrakirtithAha**||
> 
> The human lines of Gurus consist of six names- Nrisimha, Mahesha,
> Bhaskara, Mahendra, Madhava & Vishnu.
> 
> **KulArnava Tantram, Chapter 6, Verses 64-67.**


So, the point is, my badminton teacher is only a teacher but not a Guru in the strict Hindu sense of the word unless he duly belongs to any one of the lineages mentioned above. Similarly for your school teachers.

 

> Does an undeserved person can be a guru? Suppose a person has very
> much angry behavior, is he eligible to be a guru?

**No, certainly not**. In KulArnava Tantram's 13th chapter we find the descriptions of the long lists of qualities that a Guru or SaD Guru must possess. One such quality is :

 

> Vedako Vodakah Santhah Sarvajivadayaparaha| SwAdhinendriyasamchAra
> **Shadavargavijayakshamaha**||
> 
> A Guru is one who is capable understanding the hidden truths of Vedas,
> who is calm, who has compassion for all beings, who has mastered over
> the movements of his senses, **who is capable of winning over the
> shadavarga or [shadaripus][3] (which are anger, lust etc )**.
> 
> **KulArnava Tantram, Chapter 13, Verse 42.**

So, needless to say a very angry person is not fit to be a Guru. Because he is yet to master anger,  which is one of the shadaripus.









  


  [1]: https://en.wikipedia.org/wiki/Upanayana
  [2]: https://i.sstatic.net/BrQuD.jpg
  [3]: https://en.wikipedia.org/wiki/Shadripu