asaṅga : [m.] non-attachment.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]

Along with Maitreyanātha, the historical co-founder of the Yogācāra schoolof Mahāyāna Buddhismand half-brother of Vasubandhu. Born in north-west Indiaduring the 4th century ce, he was originally a member of the Mahīśāsaka school but was later converted to Mahāyāna. After many years of intense meditation, he went on to write many of the key Yogācāra treatises such as the Yogacārabhūmi Śāstra, the Mahāyāna-saṃgraha and the Abhidharma-samuccaya as well as other works. There are discrepancies between the Chinese and Tibetan traditions concerning which treatises are attributed to him and which to Maitreyanātha. 

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)

á-saṅga or a-saṅgá mfn. free from ties, independent, ŚBs. xiv (BṛĀrUp.) NṛisUp
• moving without obstacle (as a cart, a vessel, a flag, &c.) MBh. ii, 944 Hariv. &c
• having no attachment or inclination for or interest in
• ( also s.v. a-sakta)
• m. non-attachment, non-inclination Mn. vi, 75 Bh
• N. of a son of Yuyudhāna Hariv. 9207 VP
• a N. of Vasubandhu Buddh
• 'non-impediment', generally (ena), instr. ind. without obstacle Hariv. 10187 R
• (āt), abl. ind. unobstructedly, at pleasure Bālar

Sanskrit-English Dictionary, by M. Monier William

thog med

[translation-san] asaṅga

[translation-eng] {Hopkins} non-obstructed; unobstructed; Asaṅga [p.n. of one of the founders of the Yogācāra or Mind-Only (sems tsam, cittamātra) School]

Jeffrey Hopkins' Tibetan-Sanskrit-English Dictionary

thogs med

[translation-san] {C} asaṅga

[translation-eng] {Hopkins} non-obstructed; unobstructed; Asaṅga [p.n. of one of the main founders of the Yogācāra or Cittamātra (sems tsam, Mind-Only) School]

[translation-eng] {C} unattached; unhindered

Jeffrey Hopkins' Tibetan-Sanskrit-English Dictionary