Allah [may He be Glorified] said: "Verily, Ibrâhîm (Abraham) was, without doubt, forbearing, used to invoking Allâh with humility, and was repentant (to Allâh all the time, again and again ." (11:75)
Allah [May He be Glorified] tells that Prophet Ibrâhîm (peace be upon him) was "forbearing" i.e. he was of good manners with a forgiving heart and was never enraged by the ignorance of those who are ignorant.
He also "used to invoke Allâh with humility" meaning that he used to make Du'a' to Allah in all times.
He "was repentant" meaning that he was in the habit of repenting to Allah, establishing his repentance upon his knowledge, love and through devoting himself to Allah and keeping away from others besides Him.
See Tafsir Ibn Sa'di, p.342. (Al-Luwaihiq Edition).
Ibn Al-Qaiyim said: "The repentant is the one who is quick in seeking Allah's Pleasure, the one who always returns to Allah and the one who exerts all possible efforts to attain the love of Allah.
Repentance includes four requirements: love of Allah, submission to Allah, nearness to Allah and turning away from others than Him.
None deserves the title "repentant" except the one who combines all these four traits.
See Madarij As-Salikîn, Vol. I, p. 467, First Edition, Darul-Kutub Al'Ilmiyah.