Love alien's first pole erected on Earth (5)
I believe the answer is:
adore
'love' is the definition.
(adoring is a kind of loving)
'alien's first pole erected on earth' is the wordplay.
'first' indicates taking the first letters.
'pole' becomes 'rod' ('rod' can be a synonym of 'pole'**).
'erected' shows that the letters should be reversed in order.
'on' says to put letters next to each other.
'earth' becomes 'e'.
The first letter of 'aliens' is 'a'.
'rod' backwards is 'dor'.
'a'+'dor'+'e'='ADORE'
(Other definitions for adore that I've seen before include "Cherish" , "Treasure" , "Worship, idolise" , "Love to distraction" , "Worship, venerate" .)