besieging vs military blockade

besieging and military blockade both are nouns.

Word	Noun	Adjective	Verb	Adverb
besieging	Yes	No	No	No
military blockade	Yes	No	No	No

As nouns, besieging and military blockade are synonyms defined as:

besieging and military blockade: the action of an armed force that surrounds a fortified place and isolates it while continuing to attack

Other synonyms of besieging include beleaguering, siege.

besieging (noun)	military blockade (noun)
the action of an armed force that surrounds a fortified place and isolates it while continuing to attack	the action of an armed force that surrounds a fortified place and isolates it while continuing to attack