Affectionate/friendly — readily becomes attached to people; a common colloquial expression (e.g., 人懐っこい).
子猫がとても懐っこくて、すぐに指にすり寄ってきた。
The kitten was very affectionate and immediately rubbed against my finger.
新しい隣人は懐っこい人で、すぐに挨拶に来た。
The new neighbor was friendly and came to say hello right away.
彼は初対面でも懐っこく話しかけるので、打ち解けるのが早い。
He speaks warmly even with strangers, so he makes friends quickly.