The following phrase is found in many suttas:
They approve, welcome and keep clinging.
abhinandati abhivadati ajjhosāya tiṭṭhati.
About these words, AN 9.23 & DN 15 say:
ajjhosānaṁ… rooted in craving (taṇhāmūlakā)
SN 22.5 says:
They approve, welcome, and keep clinging to form.
Rūpaṁ abhinandati abhivadati ajjhosāya tiṭṭhati.
This gives rise to relishing.
Tassa rūpaṁ abhinandato abhivadato ajjhosāya tiṭṭhato uppajjati nandī.
Relishing forms is grasping.
Yā rūpe nandī tadupādānaṁ.
MN 1 says:
relishing is the root of suffering,
‘Nandī dukkhassa mūlan’ti—
SN 22.5 above, MN 38, etc, say:
Relishing is grasping.
About the prefix “abhi”, the dictionary says:
Out of this is developed the fig. meaning of increasing, i.e., an intensifying of the action implied in the verb
However, when reading SN 22.5, the impression is “abhinandati” (abhi + nandati; nandati, nand = nad) is a more subtle form of “nandi” (Sk. nandi, but cp. BSk. nandī) because SN 22.5 literally says “abhinandati” is the cause of “nandi” (abhinandato uppajjati nandī).
This topic is for any opinions on the prefix “abhi” above and the apparant more nuanced meanings of the three words above.
For example, my impression is abhinandati abhivadati ajjhosāya refer to more subtle states of mind than nandi (relishing; delight) and upadana (attachment; grasping).