think of vs retain

think of and retain both are verbs.

Word	Noun	Adjective	Verb	Adverb
think of	No	No	Yes	No
retain	No	No	Yes	No

As verbs, retain is a hyponym of think of; that is, retain is a word with a more specific, narrower meaning than think of:

Other hyponyms of think of include bear in mind, mind, keep note, characterise, characterize, qualify.

think of (verb)	retain (verb)
keep in mind for attention or consideration	keep in one's mind
look on as or consider	secure and keep for possible future use or application
intend to refer to	allow to remain in a place or position or maintain a property or feature
take into consideration, have in view	hold back within
choose in one's mind
devise or invent