The word ajaryaṃm 'imperishable' is irregularly formed when qualifying the word saṃgatam 'friendship' expressed or understood.,
The word अजर्यम् is formed from the root जृ by the addition of यत्, and affixing the negative particle अ; as अ + जृ + यत् = अजर्यं.
Thus अजर्यं नोऽस्तु सङ्गतम् 'let our friendship be imperishable'. So also अजर्यमार्यसङ्गतम्.
Why do we say 'when qualifying the word सङ्गतम्'? Observe अजरिता कम्बलः 'undecaying blanket'.,