Indistinct: (Oxford Dictionary)

Not clear or sharply defined:

Synonyms

indecipherable, illegible, barely legible, unreadable, unintelligible, unfathomable, hard to read, hard to make out

blurred, out of focus, fuzzy, hazy, misty, foggy, cloudy, shadowy, smoky, dim, nebulous

muffled, muted, dull, low, quiet, soft, faint, weak, feeble, inaudible, scarcely audible, scarcely perceptible, hard to hear, hard to make out

From a second source:

<o:p> </o:p>Distinct    
1) clearly and noticeably different; or 2) strong and definite

Distinctive    
1) having a quality or characteristic that makes a person or thing different from others; or 2) appealing or interesting because of an special quality or characteristic

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The meanings are similar, which is why they are confusing. The differences can be seen in how they are used.

Distinct
Distinct is often used to talk about two or more different things or groups of things, as in these Examples:

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- The book has three distinct parts.
- There are two distinct ethnic groups.

Distinct is also used with words like possibility and impression to mean “clear and strong,” as in these Examples:<o:p></o:p>

- A flight cancellation is a distinct possibility.
- We had the distinct impression that they were lying.
- The team had the distinct advantage of playing in their own stadium.

Distinctive<o:p></o:p>

Distinctive is used to say that one person or thing has a quality that makes this person/thing noticeably different from others, as in these examples:<o:p></o:p>

- He had a distinctive walk.
- This wine has a more distinctive flavor than that one.

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Distinctive often - but not always - has a positive meaning. Something that is distinctive is often especially good:

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- This store sells only the most distinctive chocolates.

Source:  http://www.learnersdictionary.com/qa/the-difference-between-distinct-and-distinctive

Mohamed... Even for native English speakers, understanding and using these two words is problematic, i.e., a challenge. 

Despite what many people think, these two words are seldom interchangeable. Their meanings are slightly different.<o:p></o:p>

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Distinct<o:p></o:p>

This has the meaning of ‘clear’ and ‘unmistakeable’ in the majority of its uses.<o:p></o:p>

Examples:<o:p></o:p>

A distinct odour is one which is clear, pronounced, prominent and unmistakeable.<o:p></o:p>

- ‘There is a distinct noise coming from the crowd.’ This means a clear noise from the lot of them.<o:p></o:p>

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Distinctive<o:p></o:p>

This has the meaning of ‘distinguishing’ and ‘setting it apart from others’ in the majority of its uses.<o:p></o:p>

Examples:<o:p></o:p>

A distinctive odour is one which is set apart from others for a reason.<o:p></o:p>

- ‘There is a distinctive noise coming from the crowd.’ This means that there may be an elephant trumpeting among them!<o:p></o:p>

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Source:  http://www.future-perfect.co.uk/grammar-tip/is-it-distinct-or-distinctive/<o:p></o:p>;

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